The screen on the TMo version is bigger, yes, but has the same resolution as the smaller screens. I've read in multiple reviews that the colors look amazing like on all of the Super AMOLED screens (I LOVE mine in my SGS) and this is a huge selling point to me...but I've also heard that the resolution being so low for the size of screen makes it look bad...even saw one review use the word "cartoonish" when referring to the low resolution on the large screen.
As for the processor, yes, it has a higher clock speed but the 1.2GHz procs have better GPUs. They're both pretty even. This is rather a moot point for me.
Things I do care about is being able to access the 42Meg TMo network. The clock speed, the bloatware...things like that I can change and I'm sure I will very soon after getting it. Things like the screen resolution and the network support I can't.
Anyone have the TMo SGSII? Does the resolution really look that bad? It is getting pretty close to the PPI of the G1!! 206 PPI on a brand new mega-phone like the SGSII is rough. I don't care about "retina display" hyped bs or anything...I usually don't even look at the resolution on phones because I usually can't tell much of a difference. The contrast and screen technology is more important in my eyes. **BUT** When the resolution is so low...like...almost 2008 tech in nearly 2012, low...that's rough.
For reference:
The iPhone 4 series has 326 PPI...overkill in my eyes.
Original SGS has 233...I LOVE my phone's screen. (I have the Vibrant.)
Moto Droid X has 228...totally sufficient.
HTC Evo has 217...this phone's a year and a half old!
TMo SGSII has 206...ugh...
HTC Dream (G1) has 181...unsatisfactory by today's standards.