You're not going to actually see much of a difference between the performance of the two processors.
You say " i don't wanna hear ..oh it's based if you want a keyboard or not.." but it has a great deal to do with that. Basically...
Epic:
Keyboard
Touchwiz ui
Smaller screen
SAMOLED screen
Known to have GPS problems.
Evo:
No Keyboard
Sense ui
Largest screen on the market
LCD screen
Known to have problems with dust getting under the screen.
Aside from that... EVO's running 2.2 and will likely (looking back at HTC's history) be one of the first handsets to receive Gingerbread after release. As well as the possibility of getting the New Sense UI.
Epic is running 2.1 and will likely (looking back at Samsung's history) finally receive 2.2 around the same time that gingerbread is released... that is, if they don't skip 2.2 altogether and instead push for a late release of gingerbread.