Just a few things I've noticed after running CM9 for about a month: (Note: This is all on 4/24 because I could get picture messages to receive on it, but not on the newer version)
1. Battery life is not great. Even with pretty light usage on minimum brightness and 3g, gps, bluetooth, and wifi off, I was only getting about 10-12ish hours. I would get about double that on stock.
2. Picture messaging is broken. You can receive a picture if you try send some random picture to someone (I used myself) and then click download. Also, sending pictures doesn't work.
3. When scrolling up to read earlier messages, it lags badly. If you scroll slowly though it works fine.
4. If the lockscreen is on and you open the keyboard, it unlocks the device. I actually found that to be useful, but there were a few times I pulled my phone out of my pocket and it was unlocked with the screen on. That could have contributed a little to battery life I suppose.
5. Keyboard doesn't work without automatic brightness, but someone in an earlier post told how to fix that by tweaking a setting and it did work for me.
6. Wifi has an issue occasionally where after being turned on, it tries and tries to join a network and fails until you press forget the network and retype your password. This issue only happen 5 times or so in the whole time I have been on CM9.
7. The QWERTY keyboard has two issues. Sometime it stops working and when you press buttons it opens apps sort of like short cut keys would. I don't know which keys opened what, but for an example let's say the M key would open messaging. The only way to fix this was to restart it. That issue didn't happen a lot a lot either though. The second issue involves the alt lock. Sometimes it doesn't turn it off so you just press the alt key and that turns it off.
8. Finally, the most annoying issue: When it gets to 15% battery, the red life of death starts flashing every few seconds. Over and over and over and over and over again. It is very distracting. Even after disabling the notification light, it still doesn't stop it. And seeing as how battery life isn't that great, I get down to 15% almost every day which makes it all the more worse.
All that being said, I don't expect a ROM to work perfectly. I can't thank everyone who has worked on this enough for giving us options. None of those issues are that bad at all (Red notification light comes close....)
For now, I think I'll go back to stock for the battery life. Just getting tired of having to deal with charging it so much more.
Thank you all again. It was nice to get away from the headaches of stock for a while