I love the size of the Evo, and I have somewhat smaller hands. The 4.3" screen was actually the #1 reason I was after this phone.
The iPhone does look cooler - its metal and glass, it IS sweet. But I'm not a huge fan of the OS. It's just a grid of icons. Android's interface, while a little less stable, is quickly growing into the more intuitive and usable of the two.
Look at it this way. Do you think the iPhone will ever have swype? Can I replace the shitty stock mail app? Android lets me do that. I'm not a fanboy in either direction. I love apple products, we have lots of them between my wife and I. I will buy the better product, I don't care who makes it. For me, the Evo is still it, even against the iphone 4.
Also, 4G for casual surfing is probably not that necessary. But I'm going away this weekend. I'll need local info, internet access at the hotel, restaurant reviews, etc. For that kind of use, I'm very convinced 4G will serve me well.