The EVO has an inferior display (~217 ppi versus the 326 ppi of iPhone 4) and fairly poor battery life, however, especially with 4G enabled. Apple claims the battery in the new model could last 40% longer than the battery in the 3GS. The EVO's heavier as well: 170 grams versus the iPhone's 137 grams (a hair heavier than the 3GS).
It isn't so cut and dry.
Most people would consider the HTC EVO superior in spite of such things considering everything else.
No phone is ever best for everyone, that's simply impossible to do even in spite of Apple's consistent marketing gimmicks that would have you believe otherwise.
Personally, I find the HTC HD2 to be "superior" to both the iPhone 4 and the HTC EVO myself - it's got what I want in a device in spite of the other two being "superior" in their own respects for those that choose to look at them as such.
PPI is far from "the ultimate judge" in terms of display quality. In my experience, every time someone complains or whines about a 4.3" or larger display does so based on no hands on experience - but get that person a device with such a screen size and let them actually use it for a period of time then you'll get something like this:
"I thought it would be too big, originally, but after having used it, I can't really see myself using anything smaller ever again."
Increasing the resolution of the iPhone is fine but it's not the end-all-be-all. I love the additional market gimmick of "Retina Display has a resolution that is so high the human eye can't even see the pixels" which is such utter absolute bullshit it's not even funny.
I can see the pixels.