Well, I've only had mine for a couple of days so there are probably flaws I have yet to find. So far, however, it's magnificent. I just migrated from a TouchPro 2 with a custom rom. Some notes:
Battery life. Fine by me. Same or better than TP2. Just keep Wifi and BT off when you don't need him. Charged the phone while on, then turned it off while still plugged in and let it finish charging (read this somewhere; the charge LED turns green, but if you turn it off it goes amber again and charges for another 20 minutes.) Listened to about four hours of music, used wifi a few times, made a few calls, played with apps and it was at 30% after 30 hours.
Screen: lovely and delicious. Clear, rich colors, dense pitch and very receptive. Yes, when on auto-brightness it's dim in daylight. But then I put the power control widget on my home screen which has a button that cycles between full, low and auto adjust. At full the display is perfectly fine on a sunny summer day in San Francisco (yes. we have one or two of those). I'm still getting used to capacitive vs. resistive (can't use my fingernail but who cares? Nice solid feel to it, no real accuracy issues except portrait keyboard. I'm still used to the incredible physical keyboard on the TP2 so I'm withholding judgment.
Speed. Excellent. Nothing more to say. Again, early to tell but Android does a really good job of memory management. An app's state is recorded when the user leaves it for another app; then the system aggressively usurps resources when it needs them without waiting for permission. I see no appreciable lag in returning to fully closed apps like the web browser. I wish my desktop were that good.
I love the form factor. It's a slim phone, and light but not toylike. I don't like HTC's back covers; they feel flimsy and cheap.
Call quality is really great with the earpiece; I haven't tried speaker yet but I don't expect it to beat the TP2.
Maybe my expectations are low but I think it's an awesome device that will get even better with the new FroYo update.