Angry former EVO user. Gone through two EVO with all the waiting, screen separating, crooked volume and power buttons, slow 3G internet connection, non response to new settings, crooked back plate, bad HD video recording (video and sound), yellowish tinted wash out screen and the constant stutter when scrolling.
The Epic has non of the issues mentioned above and the most rumored issues such as the GPS works great. The S-AMOLD screen contrast and color is amazing you have to see it yourself to believe it. I really gave HTC a chance since the EVO was my first smartphone but comparing it to the Epic, they just have too much QC and design problems. The specs on the the HTC phones all look great, but the way they put all those goodies together just needs more improvements and refinements.
Also I think the biggest difference between the Epic and the EVO is the video recording. Just did a couple of sample 720p videos right after I got it and the quality of the video and sound of the Epic is just soooo much better than the recordings on the EVO both indoor and out. Really, go try it out and see for yourself.