For those that read my Galaxy Note review, I thought it was a good device, it had a number of good things as well as many shortcomings. In general it wasn't suited for everyone. The SGS3 is better suited for the masses.
At 4.8" it's large for iPhone users and feels fresh for most Android users who are used to 4"+ displays. It's pocket able, even in my gym shorts it didn't have the extra bulge the Galaxy Note had. I've been using the Galaxy Nexus recently and suddenly felt awkward with the S3 having physical buttons again. I know the Android purists are going to say the S3 is 2 step forward and 1 step backward in design by incorporating the big home button and the back and search buttons.
After a week of use I did think the home button is a bit awkward to use but it does come in handy when I'm driving and didn't want my eyes off the road.
Design & Build quality 3.8 / 5 Stars
Let's face it, the iPhone still beats Samsung in design and engineering. The Samsung shell is all plastic not very different than plastic found on free phones. The design of the S3 carried over from the Galaxy Note.
I felt the S3's alum accented trim on the side to be extra slippery compared to the iPhone 4. Unless you have really rough and sticky fingers this phone can slip very easily. The side profile is way too tapered and not flat making it difficult to get a good grip. So I highly recommend getting a case right away.
The battery back door pops off just like the Galaxy Note, this time the S3 uses a Mini SIM card just like Apple. The Micro SD card is in a very good location and can easily be popped out without powering off the device.
Overall, it's a solid design chasis does have some flex and not as rigid as the HTC One X or iPhone.
Call quality: 4.5 / 5 Stars
AT&T LTE service is a huge improvement over their 3G service, not only is the signal quality better so was the voice quality. SGS3 has a very loud earpiece speaker that sounded almost as loud as having the speakerphone turned on. I was very pleased with the call quality.
Battery Life 3.5 / 5 Stars
I wasn't blown away by the battery life, in general it was worst than the Note due to the smaller battery. It was actually worst than my modded SGS2 running CM9. It took me awhile to go through preferences and tweak the phone for good battery life. After the power adjustments, battery life improved substantially but still nowhere near the Galaxy Note. Leaving the device fully charged on overnight without plugging in, it dropped by only 7% in 6.5 hours of discharging. Much more improved over the 1st night when I had the device dropped 13% by the morning.
Performance 4.3 / 5 Stars
Given that the US Spec version also uses the DualCore S4 Krait just like the HTC One X, the reason being Samsung's Exynos QuadCore does not have the US LTE baseband radio yet. I don't think Quad-core is worth getting especially taking an old ARM design and simply doubling the cores. The only reason for opting for the QuadCore International version is for the faster GPU which is currently the fastest mobile GPU available on a smartphone, the iPad 3 one is king of all mobile devices for now.
I do appreciate that Samsung gave the US Spec S3 a bump to 2GB of memory instead of 1GB found on the SGH-9300 or International S3. The device really does not slow down or bottleneck much with multiple apps running at the same time and it's pretty evident that a memory task manager isn't necessary anymore with 2GB. Imo, this is quite possibly the best feature of all the smart phones out today.
Here's a quick snapshot of ATT LTE performance.
Not bad, it's not as good as the VZ LTE service where I constantly get between 4-14mbs.
Screen Quality 4.5 / 5 Stars
The screen was the star of this release. 4.8" of gorgeous qHD display. This screen actually is an improvement over the SGS2 and Note in particular the SAMOLED panel didn't have green or yellow color balance issues. Most review sites gave the nod to the HTC One X's S-LCD2 for the best looking display. I actually disagree, I think the HTC One X probably has the most accurate color but it doesn't standout as much as the SGS3's great contrast ratio. Blacks and whites are just much crisper looking on the SGS3. I've had the HTC One X next to the SGS3 around a couple of guys at the office and almost everyone picked the SGS3 over the HTC for best looking display. I guess the extra 0.1" also helped make the phone look bigger.
So is this the best smartphone in America today? I have to concur with most review sites, it does do most things better than the iPhone and more. It also depends on your preferences and taste. My boss uses the Galaxy Nexus and he has no friggin clue how to task switch or install a different launcher. Like many he's better suited with an iPhone but he hates Apple.
Two things the iPhone still does better and that's SIRI and Photos. While most people dismiss SIRI as just an improved voice command app. I have to disagree I think voice command is huge in the next decade as it's the next level of user interface. SIRI in the beta form can understand normal human spoken voice much better than any other voice command apps that I've used and the S-Voice included in the S3 is just a simple copy and I'm sure Apple has a lawsuit ready.
As for picture taking, while the S3's camera app improved greatly, mostly due to ICS improvement. The software is still somewhat clunking, many sites have reported that Samsung does do a little cheating to enhance the photo a bit after snapping.
Well, if you are on the fence on which Android device to get. I'd say the S3 over the HTC One X for sure. The HTC One X is really superior to the S3 in so many areas but the most glaring weakness is the lack of the MicroSD card and non-removable battery. 2nd area is the S3 has 2GB of memory which is a huge performance boost for those who actively use a lot of apps. HTC Sense UI is better than Touchwiz but once CM9 is RC for S3 than it will be king for sure.