Here's my 2 cents:
* I've noticed that the phone doesn't seem to vibrate when in "silent" mode. IE, turning the ringer off during a movie.
* The hard-button backlighting has been really temperamental in when it decides to illuminate.
* I don't mind the vibration when making calls, but I do miss the short beep when hanging up with a call. Can we have that back? Or maybe make it vibrate on hang-up too?
* I too have noticed the screen brightness sometimes being locked full-bore, although I haven't associated it with the camera like others have. Additional play time may uncover what's causing it.
* I'll echo the alarm clock problem. Settings have been checked and changed around. Sometimes it'll be making noise with no GUI to shut it up. How do you break an alarm clock?
* The battery life! What the hell? I don't use my phone very heavily, and I'm in the 30% range when I go to bed. It used to be in the 60's.
* I haven't noticed missing any calls during data usage, but I don't receive all that many calls. Again, my phone doesn't see particularly heavy usage.
* Voicemail doesn't download very reliably. It may be due to the 3G "sleep" problem others have mentioned. HTC weather widget (no info and not updating) problems seem to go with it. Rebooting the phone doesn't seem to help.
* The delay between receiving a call and the phone actually ringing is pretty painful. Sometimes the phone will ring for only a second or two before dumping to voicemail. Even when I catch it ringing, it'll sometimes take 3-6 seconds from when I hit the green button or swipe it for me to get past the "incoming call" screen and actually get to the call. This is really unacceptable. Doesn't 2.1 allow "prioritizing" computing threads?
* I've not noticed any BT problems yet. For those of you having problems, check to see if your device has a BT update. The new BT capabilities of this phone means it's using slightly different protocols. If your device doesn't support the new programming, you'll have problems.
* The keyboard has been functioning okay for me. (portrait and landscape)
* Cell-based (coarse) location still seems to work fine. GPS (fine) location makes it more accurate when on. I checked this with google maps, so it's probably app dependant. Some apps may have to make a special callout for coarse location activation, whereas they needn't pay special attention to it before in 1.5.
* Facebook contacts can removed (or hidden) if you like. Play with your phones a little bit, people!
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I agree with some of the comments.
This update took far too long to roll out to be having some of these issues. Little quirks here and there are one thing. A few of these issues shouldn't have made it past beta testing, much less a "final" release. Did Sprint/HTC test this before rolling it out? I mean, these are apparently common issues that are noticable within 24hours. Come on guys, step it up!
All that being said, I like the direction 2.1 on this phone is going. However, I really hope they don't drop the ball on fixing the more prominent problems. I'll be a really unhappy camper if I have to wait another 6 months for any kind of attempt at a maintenance update.