Well, for me, its the Evo 3D all the way. Here's why:
1. Evo 3D has more ram. No, the the ram is NOT there to accommodate the 3D aspect. The LG Optimus 3D only has 512 MB of ram and has 3D UI interface, which the Evo 3D doesn't. This means more apps saved in queue in the background.
2. Though the sensation looks better (meaning its slimmer and curvier) I like the manly commanding and authoritative look of the Evo 3D. It looks like a sleek phone for professionals. Of course, aesthetics is a very subjective argument.
3. The 3D Aspect of the EVo 3D is FOR PHOTOS AND VIDEOS ONLY. There is no "3D" UI interface, like the one found on the Optimus 3d/ LG Thrill. The UI on the Evo 3D has the same UI as the Sensation.
4. Dedicated camera button. Need I say more?
5. More internal storage. The EVo 3D has 4GB internal storage, compared to the Sensations 1 GB. That means more apps can be stored on the phone itself, freeing up more room on your memory card.
6. OK, I'm gonna state the obvious. It friggin takes friggin 3D pics and video man (Which you can switch to 2D at your heart's desire). And they are including the mobile version of friggin youtube 3d....
7. front facing camera on the Evo 3D is 1.3 mp. The Senastion has a VGA front facing cam.
8. Sprint has Google Voice integration, making your Evo 3D's Gvoice functionality a tad more superior than the Sensation.
9. Evo 3D has a bigger battery.
10. This one is a stretch. The rear camera is only 5mp, but there are 2 of them back there. I'm sure that at some point down the road, an ingenious app developer will come along and make a nice little app that takes advantage of that second camera.