Had to clear up space, but the big download and install went smoothly. (Over-the-air update via T-Mobile in Austin, TX, USA, if anyone is interested.) All my stuff still there afterwards. Some new stuff I have noticed:

• Better phone log - I can actually see what number my contact called from and call them back on the same number. (No "open contact" button, though.)
• Applications are alphabetized on the More Apps list. Not just stuck in order they were last loaded/updated
• Front camera much improved. Still not great, but passable with decent light. Big bar on the right is gone. (Tested with the mirror app, which even before this upgrade would impress even the most stalwart fanboi of other phones.) This should make the front camera useable, though maybe not for quality video calls yet.
• Holding down the 1 key on the keypad dials voicemail...just like on other phones.
• Snappier performance, though that may be my imagination...we'll find out throughout the next few days if it stays snappy or was just from the reboot
• I have become thinner and better looking (verfied by using the mirror app)