I spent 2 weeks with the HTC EVO LTE 4G, the one I had, had problems with 3G data and receiving calls. The screen was better on the EVO, and I miss the kickstand. I prefer the intergration of sense, so far, but that maybe because of using nothing but EVO's since they came out. The SG3 is its equal in many other ways, and so far bests it in a few others.
The multitasking is far superior to the EVO. I also prefer the HTC keyboard.
The multitasking on the EVO is disapointing, if you can get past that, you can't go wrong with either phone.
All in all, I think the SG3 does what it suposed to do smoother and as it was meant to be done, better than the EVO.