I did last night, below are some initial thoughts/notes:
1. My firmware version still shows "2.02NA , Wed, 7, Oct, 2009", I'm not sure if that's normal or something didn't take.
2. It seemed to retain all settings except for the host and wireless settings, so if you don't like resetting those by memory back stuff up like it says.
3. My WAN speeds seem better, but it might just be the reboots. WAN speeds for me have been around 1.5-1.8 MB/s instead of ~2.25 MB/s. I know the 825 can be higher because the speeds are fine for awhile, I can't find a pattern, thought other wan activity seems to slow it. Even my ancient WRT54G router could max things out 100% of the time. Maybe I have a lemon, but I'm amazed and can't believe xbox 360 and SIP issues were fixed before any more major performance issues, if I understand the changelog correctly.
4. mIRC connections repeatedly die for me after the update. VPN and other constant connections are fine. I modified my client with a little hack and it seems to stay alive now, but something definitely changed there.