I've got both, and can't decide which one to keep also.
The Inc's LED screen has much more saturated colors (almost too saturated), which makes the EVO's screen look washed out when side by side. The EVO, however, is much more usable in sunlight.
In my area, I'm getting about 2mbps download on the Inc's 3G. On the EVO I'm getting about 4mbps on 4G, and 1.5 mbps on 3G. I live on the fringes of Baltimore's 4G network. Last night I went to the heart of the city and was getting 6mbps on 4G with the EVO.
Even though both phones have the same processor, The Inc. seems to be a bit faster when opening programs. Screen refreshes are also faster on the Inc.
I do miss the trackball on the EVO, but it is not a deal breaker.
One thing that really bugs me are the power and volume rocker switches on both phones. They are a bit too recessed, making it harder to use these controls. This is one area where Apple really did it right on the iPhone.
In my experience, reception is better on the EVO, on 3G, compared to the Inc. About an average of 10db.
So, at this point, I really can't decide which one to keep. I almost feel like returning both and re-activating my old Moto Star Tac. Too many choices.