I've been very much satisfied with v1.22NA, don't do reboots for weeks, and even then usually rebooting just for the heck of it (if for some reason internet slows down, just to make sure it's ISP and not router, I do router restart)
As far as I remember in v1.02 I had problem with UPnP, it didn't work properly, but it was very stable.
As of cooling issues, no problem there either, yes, it's little warm, but nothing to be alarmed about, unless of course it's hot in the room itself (I keep room temperature no more then 25C)