The dirty truth about the EVO is that once you see the 4.3 inch screen, and how useful it is, you just can't go back to a smaller screen. I really don't care whether the phone is Android or Apple, OLED, Super AMOLED, or LCD, if the screen is less than 4.3 inches it doesn't suit my needs.
Sadly, I am afflicted with less than 20/20 vision so small screens like that of the Hero, Eris, Aria, or even Incredible (even though the Incredible has a sweet trackpad), are just difficult to see in real world conditions such as my morning and evening commutes. Matter of fact, I think I could comfortably go as high as 4.5 inches for a mobile phone screen.
If Apple would have gone with a bigger screen for the iPhone 4, Android would have had trouble on its hands... As is, screen size remains a key distinction between Android (EVO with Sprint; Droid X with Verizon) and the iPhone.