The Pre had a lower GPU then Evo. A more colorful screen, but not a better GPU. Then the CPU makes the Pre a paper weight. Show me a 3d game for the Pre, that there is an Android version of it, that plays better on the Pre.
I can tell you right now that Dungeon Hunter, yet another Gameloft game that was ported from the iPhone to the Pre and then to Android, looks better on the Pre than on the Evo. The framerate is a little faster on the Pre, but it is still very playable on the Evo, however, the textures look quite a bit better on the Pre, also, the lighting effects look better on the Pre as well. When you run around the dungeons on the Evo, it looks like someone installed an electrical lighting system in that dungeon, compared to the Pre version where you get more of a real dungeon feel.
Asphalt 5 is another game that runs better on the Pre. While the slightly updated version runs better now than it did before on the Evo, it's just a tad bit slower and has occasional pauses that you won't find on the Pre version. Of course, to play any Gameloft game on at least a Sprint Palm Pre, you better do a lengthy reboot if you want to avoid a "Too many cards" error. It's very enjoyable to just start one game after the other on the Evo without having to reboot between each one. And of course the big screen of the Evo also makes for a better experience, because if you have big thumbs, you will cover up almost half of the Pres screen when playing.
Need for Speed Shift looks smooth on this demo running on a Nexus One:
YouTube - Need for Speed Shift for Android
Not sure when we actually get to buy this game. I am tempted to get it because it does look like the hands down winner for any mobile racing game.
Lastly, check out this article, it brings up some interesting insights.
Hummingbird vs. Snapdragon: The 1 GHz Smartphone Showdown | AlienBabelTech
If you like your eyes, I highly recommend copying and pasting this into Word or Wordpad, the black background with white letters will kill your eyes.
Oh, and I bought Heavy Gunner 3d. Very fun game and runs good on the Evo!