Aesthetics: very pleasing, feels like a solid block of metal with a soft touch plastic wrapper. The weight is just right, not like my Fascinate which was so light it felt like a toy.
Screen: Screen quality is quite good, seems a bit better than Evos I've demo'd. Colors are bright, not Super AMOLED bright, but text is much sharper.
Hardware: Overall seems very nice, well constructed, no build quality issues. Volume buttons seem almost too easy to press, and not a big fan of the micro-USB on the side.
Phone - including bluetooth & speakerphone usage: Voice quality is good, volume is plenty loud, haven't tried BT, I hardly use it.
Overall User Interface (including HTC Sense): Sense is very friendly, I'm a Launcher Pro advocate, but I may stick it out with Sense for a while.
Widgets: Sense widgets are useful for many people, not my cup of tea.
Signal quality (Compared to other devices): Seems to pull a much better signal than the Fascinate in all areas, 3G, 4G and wifi
GPS: it works, and that's a good thing!
Social Networking: I don't use the stock apps, I'm hooked on Tweetdeck to unify my Facebook and Twitter feeds in one place.
Email/Calendar: Sense versions of these apps are the best around, period. All the features you need are there.
Battery Life: unknown
Performance: very speedy so far, lag free. 4G speeds are awesome.
Media (music, movies, DLNA): Music player works well, streamed shoutcast with Winamp for 45 minutes without a hiccup
Keyboard's: Sense keyboard is decent, downloaded Swype beta and it works great
Camera (both still & video): took a few sample photos, no complaints at all. Camera app has more features than the Fascinate, focuses fast and takes the picture instantly
How the Thunderbolt compares to your previous smartphone (if applicable): I think it's a big step up from the Fascinate, that phone was glitchy from day one, and very laggy. For example, selecting 20 messages on the Samsung to delete from my work Exchange account would take 30+ seconds, the TB deletes them in 1 second. I always had trouble connecting to wifi at work using PEAP, the Thunderbolt worked flawlessly the very first time. Shoutcast streams never played on the Fascinate, on the Bolt it works exactly as it should. I'm very pleased.
Disappointments (if any): While good to have 4G all around Denver, at my house in the suburbs I'm still on 3g. Umm, that's not the phone's fault...