If it ain't broke, don't upgrade it
Things turned ugly, however, when I connected to my company's VPN over the wireless connection (it worked fine over a wired connection). After about a minute, the router would reboot itself and dropped all connections. A little Googling showed that other people have had the problem, and that there's no resolution yet. This firmware version has been out since October, so it stinks that they haven't fixed it. After downgrading to the previous version of the firmware, the problem disappeared, but I wasted almost half a day working on it.
Incidentally, there's lots of good information on various vendors' networking hardware over at Broadband Reports. I won't again make the mistake of upgrading the firmware before consulting that site for known issue. I should have known enough to check there in the first place - I had problems with firmware upgrades on my first wireless access point too.