So far, I'm very impressed by the speed of the device. Running a speedtest on my OG Evo (over wi-fi) provides me with approx 5.2Mb/s down and 90ms ping. The same test on my EVO LTE gives me a little over 10Mb/s down and 70ms ping. This is using an ASUS RT-N56U router on a 50MB/s connection, so the phones' wireless cards are definitely the bottlenecks here.
The menus are nice and fluid. Apps start quickly. I do miss the "menu" button at the bottom of the phone, but I suspect I'll get used to the on-screen one.
The screen is gorgeous. The battery seems to be _great_ (I have LTE turned off, as it's not available here yet). With moderately heavy use (installing apps, movie data, activating, calling people, watching videos, and litttttle bit of idle time), I've used it for 3.5 hours and I still have 78% remaining. My Evo would be much closer to dying at this point.
I like the kickstand, but I have trouble engaging it-- my fault for biting my nails, I suppose.
The camera looks great, but I can't get good lighting here to really test it out well yet.
They've definitely improved Sense-- the widgets are more varied, everything has a bit more polish to it.
I feel like it's a complete and utter iPhone killer, but unfortunately it won't get the sort of marketing $$$ behind it that the iPhone has.