w00t~!1!!!@!one
I've upgraded from .266 and really I have not noticed any memory leaks (as previously mentioned) or speed increases. Been running it now for over 5 hours. The initial reboot, after upgrade took about 28 minutes whereas previously a battery pull reboot would be about 12 minutes. Confirmed it again with a batter pull: reboot time is about 31 minutes. No big deal for me though.
It seems about the same speed as .266. 2G, 2G &3G all work for me. I can use Pandora and email across both network schemes. My memory hovers around 35-28mb and all my apps work. BBWeather, googlesync, logicmail, Pandora, Pocket Express, AmazeGPS, google maps, Poynt, Trapster....
I had to re-enter some of the firewall settings but no problems at all.
I am on regular AT&T and I now have the option of 2g and 3g & 2g, so I can confirm this as the others have noticed.
Overall, if yer l33t go for it! Otherwise, nothing gained as far as I can tell.... that is, besides braggin' rights with friends.