I know it's a little off topic but I would really love to hear you reasons.
I'm in the same boat as these other guys. I had the Evo LTE for 14 days and returned it because of the multitasking issues and a couple of other little concerns. I plan on trying the GS3 for a couple of weeks (I've never owned a Samsung phone before) but if I don't like it I'm definitely going back to the Evo.
I've recently heard people saying that one of the reasons that the GS3 is faster and gets better battery life is because it's running the 4.0.4 software as opposed to the Evo which is running 4.0.3. I'm kind of intrigued by this idea that the Evo may have some major performance improvements once that update is delivered.
With apologies to the OP, I'll engage, but try to keep it out of the troll-zone. I was only over here on curiosity because I'm a phone geek in general with no fanboy affiliations to any particular brand (except that I can't stand Apple), and this thread caught my eye.
TBH, I was stuck on an Optimus S, itching to upgrade, and got caught up in the LTEVO hype before I knew anything firm about GS3 availability. Got it on the first day pre-orders were shipped. I'm not the kind of person that can jump around on phones every few months, so I wanted something that I could live with for the life of the contract.
I'm a big believer that any software shortcomings can be fixed (I was a ROM-whore on my Optimus), but you're stuck with the hardware - internal specs and overall look/feel of the phone itself. Developer support is already through the roof over on XDA, and once HTC finally releases the source code it's only going to get better. I'm sure the the GS3 will have similar support as popular as it is.
Specs being pretty much a wash (though the extra GB of RAM would be nice), it comes down to the form factor and the display for me. I played with some other Samsung phones and just did not like the way they were constructed. They felt cheap and plastic-y compared to the LTEVO. I was also concerned about reports of subpar GPS/WiFi/cell radios on Samsung phones.
I did not like the display of the Samsungs I played with - the colors seemed oversaturated and cartoony on the Note, dark and just "not right" on the GNEX. Going back to the LTEVO was a relief to my eyes. Crisp, clean, just right. Jury is still out on GS3 display because I haven't seen one in person, I could only go on what I saw at the time and knew that the GS3 display was based on very similar technology.
I also just don't like the way the GS3 looks, which is just a personal opinion and not an affront to those that do like it. Some people think the LTEVO 3-tone back is ugly - I like it.
These are just my opinions and I go with what works for me. Your opinions may differ and something else may work for you. The beauty is that you can't go wrong choosing between the two. We're talking Rolls vs Bentley while everything else is out there is Chevy and Ford. These are great times for Android and Apple knows it.