Which phone should I choose?

I'd choose the S3. I have a Samsung Galaxy Ace S5830 right next to me and it's working like a charm. I can call and text people, which is pretty much all I need.

Just kidding. The camera is pretty good unless you're a professional photograph, the cpu is fast enough (tho no java), and it looks nice.

Nokia.

I have a HTC One X and it is a monster... Only the battery is the only negative thing om this phone

I'd go with the S3.

I'm an s2 owner so a bit biased (as the s2 is awesome) and would say s3 but I've heard good stuff about the One X as well.

Would say One X. HTC phones tend to be higher quality than Sammy's.

Also, consider the Nexus 4. I've recently got mine and its been a wonderful product.

Nexus 4 FTW.

S3

HTC One X

I would go with the HTC One X!

S3, but grey or pebble blue are better colors :)

S3 because the One X doesn't have SD card slot. What kind of idiocy is that?

DISCLAIMER #1: I tinkered a bit with a friend's HTC One X, but i do not own it. I own a S3 but I am migrating to a Nexus 4 as it's Google-supported and as open-source as possible.

DISCLAIMER #2: Sorry, this post got longer than I expected.. But no TL;DR from me :P

Except for some games, most software isn't optimized for Tegra; thus, S3 will effectively perform a bit faster overall. The S3 has AMOLED screen (vibrant colors but awful sharpness) while One X has LCD (better sharpness, but less visibility under sunlight). It's a question of taste, tho.

The user interface on One X resembles Google's standards more closely . TouchWiz does divert from the original Android experience, but it doesn't suck as much as people will complain on forums; it's so feature-rich (Smart Stay / Smart Rotate / Multi-Window) it may be worth it.

S3 also features better battery time on stock configuration. The Tegra CPU/GPU architecture is just so complex compared to Exynos it's hard to get it right; also the S3 features a 32nm chip (compared to One X and its 40nm process). But please note both smartphones can get a generous battery life increase if you do root it and choose a decent ROM / kernel.

Now, if you are an advanced user... One X has the S-On/S-Off problem, while the S3 is way more unbrickable. Developers probably dislike / hate both platforms (bad support from both Samsung and HTC), but S3 seems more hackable nowadays.

iPhone 5 is best!

i have the samsung galaxy s3 and it is fucking awesome, I recommend it 100%, I can't imagine a better phone, everything is super smooth.

I have HTC One S and its powerful, but:

galaxy s3 > htc one S > others > iphone

S3

I'd choose the S3. But, you may also take a look at THIS

smart phones sucks , go with an oldschool nokia.. ;)

S3 would be my choice.

Personally, I'd scrap both and go for a Nexus 4 (faster, no bloatware and a lot cheaper to buy unlocked). I have one and absolutely love it. But out of those two, I'd go for the S3.

S3

S3. I have one and LOVE it. Especially the split screen feature

I would also suggest looking at the Nexus 4 if you have an option. I am using it and it's a great phone. If not the S3 would be my 2nd choice :)

Personally I'd go with the S3 but then again I've got an S2 now so I might be a little bit biased. :P

The S3 has really brought some interesting stuff to the table while keeping the expandability that so many have left out. I find the recent HTC phones lacking in many ways.