The iPhone 4 is no small thing to review. As most readers of Engadget are well aware, in the gadget world a new piece of Apple hardware is a major event, preceded by rumors, speculation, an over-the-top announcement, and finally days, weeks, or months of anticipation from an ever-widening fan base. The iPhone 4 is certainly no exception -- in fact, it may be Apple's most successful launch yet, despite some bumps on the road. We've already seen Apple and AT&T's servers overloaded on the first day of pre-orders, the ship date for the next set of phones pushed back due to high demand, and die-hard fans in lineoutside of Apple locations a week before the phone is actually available. It's a lot to live up to, and the iPhone 4 is doing its best -- with features like a super-fast A4 CPU, a new front-facing camera and five megapixel shooter on the back, a completely new industrial design, and that outrageous Retina Display, no one would argue that Apple has been asleep at the wheel. So the question turns to whether or not the iPhone 4 can live up to the intense hype. Can it deliver on the promises Steve Jobs made at WWDC, and can it cement Apple's position in the marketplace in the face of mounting competition from the likes of Google and Microsoft? We have the answers to those questions -- and many more -- in our full review, so read on to find out!

Hardware

Perhaps the most notable change with the new iPhone is the drastic industrial design overhaul -- Apple seems to have completely rethought its strategy on how the phone should look and feel, and the results are nothing if not striking.

Industrial design

In his WWDC keynote, Steve Jobs likened the design of the iPhone 4 to that of a "beautiful, old Leica camera," and as we've said before, he wasn't off the mark. Instead of hewing to the curved, plasticky, silver-bezeled look of the iPhone 3G and 3GS, the company has turned the casing and face of the device into something decidedly more detailed and sophisticated. From the design aesthetic through to the actual build process, Jony Ive and his team have reset what we expect in an iPhone, coming up with something that clearly harkens back to the retro-future Braun designs of Dieter Rams. The iPhone 4 is made up of three basic parts: two pieces of smooth, strengthened glass, and a stainless steel band which wraps around the sides, top, and bottom of the phone. The effect is clean but not simple, and Apple has added little details, like altered volume buttons (what used to be a rocker is now separated into circular clickers labeled + and -), and notches in that metal band which serve to improve radio connections (more on that in a minute). The phone is noticeably thinner than the 3GS at .37 inches compared to .48 inches, but it weighs the same 4.8 ounces, making the whole package seem tighter and denser. It feels great in your hand, with good heft, although it might take a little time to get used to the lack of a rounded back if you're coming from the 3G or 3GS.

Internals

It's not just the face of the phone that's undergone a transformation -- the iPhone 4 is all new inside as well. For starters, Apple has moved on from the Samsung-built ARM Cortex-A8-based CPU used in the 3GS to its custom A4 chip used in the iPad, which funnily enough... is an ARM Cortex-A8-based CPU. While the company hasn't yet said what the clock speed of the processor is, we're guessing it's something below the 1GHz touted for its tablet cousin. The phone is definitely snappier than the 3GS, so we're not about to volley complaints just yet -- in particular, graphics seemed to render faster, and overall responsiveness was slightly higher, though admittedly, it wasn't blowing the doors off the joint. It's certainly faster, but the 3GS wasn't hurting on speed to our eyes, so it's not as wildly noticeable a leap as the 3G to the 3GS.

As usual, Apple isn't fessing up about the RAM situation, though we have on very good authority that the iPhone 4 has 512MB onboard, a big step up from the 256MB in the previous model and the iPad. We would have liked to see it futureproofed with something like 1GB, but then again, Apple's got to sell a new phone in a year. As far as internal storage goes, you can buy the new iPhone in either 16GB ($199 on contract) or 32GB ($299 on contract) capacity -- fine for now, but since the company has just introduced 30FPS 720p video recording, you could find yourself outgrowing that number pretty quickly. It's a little odd, in fact, that the company didn't double down here and bump the capacity to 64GB, as it's recently done with the iPod touch. In terms of wireless, the iPhone 4 is packed with an 802.11n WiFi radio, as well as a quad-band HSUPA chip and Bluetooth 2.1.

The redesigned housing allows for a much larger lithium-ion battery on the inside, providing improved numbers for Apple's life ratings (more on that in a moment), though it's still not easily replaceable. Additionally, the new phone has those two new cameras (VGA up front, five megapixels with LED flash around back), a new second microphone used to combat background noise while on calls (similar to the Nexus One), a gyroscope in addition to the standard accelerometer, a light sensor, and a proximity sensor. As with the 3GS, an AGPS chip and compass are bundled somewhere in that tiny frame as well.

Of course, the big internal story is what has become external: namely, the UMTS, GPS, WiFi, and Bluetooth antennas. Apple has made the stainless band around the phone essentially a couple of big antennae, and they seem to be doing a pretty good job at hanging onto radio signals. The big question is obviously whether or not this fixes or helps with the constant dropped calls iPhone users on AT&T's network have gotten used to. Well in our testing, we had far, far fewer dropped calls than we experienced on our 3GS. Let's just say that again: yes, the iPhone 4 does seem to alleviate the dropped call issue. It wasn't perfect, and we had some connection issues in downtown New York City in particular, though it's tough to say if it was the fault of our phone, the cluster of buildings we were near, or the person we were speaking to, who was on a 3GS in the same locatio

Display

By now you should know that iPhone 4 has an all-new display, as well. Apple is calling the LED backlit, 960 x 640 IPS screen the "Retina Display" due to its high resolution and pixel density. At the same 3.5-inches as the older screens, the new display manages an insane 326ppi pixel density along with an 800:1 contrast ratio. Steve made a huge point about the science behind this technology during his keynote, claiming that the resolution of the screen essentially tops what is perceivable by the human eye. There have been some debates as to whether or not this argument holds water, but we can tell you this: to our eyes, there has never been a more detailed, clear, or viewable screen on any mobile device. 

Cameras

The cameras on the new iPhone are going to be a topic of much debate, since this has been an area where Apple has been slow to innovate. The 3GS sported a measly three megapixel shooter with few bells and whistles (and no flash), and while it was fine for quick snaps, it wasn't an artist's tool by any means. The company finally seems to be listening to a public that's interested in leaving the point-and-shoot at home in favor of a phone with a capable camera, by adding a five megapixel shooter to the backside of the iPhone 4 and a VGA camera up front.

Let's first take a look at the higher-res main camera. At his WWDC keynote, Jobs said that getting great looking images wasn't just about upping the camera's megapixels, but had more to do with grabbing more photons. Increase the photon count, let more light in, and your images will look better, the thought goes. So Apple's using a newer backside-illuminated sensor that's more sensitive to light in addition to upping those megapixels -- and we must say, pictures on the iPhone 4 look stunning. Our shots looked good right out of the gate, with few problems when it came to focusing or low light. With the flash on, we managed decent if somewhat blown out results (fairly common with smaller LED flashes) though impressively, the iPhone 4 was usually able to take completely useable and even handsome photos in fairly low light without the flash. It seems like that photon situation is definitely in play, because even shots taken in fairly dark lighting came out looking good. Autofocus worked well in most situations, and we were actually able to get some impressive looking macro shots (see the flowers and Penny below). In general, we'd have no trouble using the iPhone 4's camera as a stand-in for a dedicated camera. Not only did it take beautiful shots, but the A4 and iOS 4 combo have considerably sped up the time it takes to snap pictures -- it's now almost instantaneous. Otherwise, you have options for a 5x digital zoom (which produces results that look like a digital zoom) and basic on / off / auto settings for the flash. It's pretty bare bones, and we wouldn't have minded a few basic options like white balance settings -- but c'mon, this is Apple we're talking about. Luckily, the App Store is chock full of applications that improve upon the stock camera app -- we expect to see a handful of new ones that take advantage of the new sensor soon.

iPhone 4 camera shots

As far as video goes, we were definitely impressed by the 720p capture, though there are stability issues with the lens and the all-too-familiar "jellyvision" CMOS issues that tend to rear their head if you're not holding the phone very steady. Still, we can't see carrying around a Flip HD instead of just keeping this in our pocket (though as we said, we'd like to see a higher storage capacity). Everything we shot looked crisp and mostly artifact-free, and we didn't see any hiccups in the 30 FPS rate Apple claims, even in lower light. Adding iMovie to the mix for on-the-fly editing is a nice touch too (more on that in the software section). The video below was shot and edited completely in-phone, so enjoy