Mine is very stable and fast. Got it in November, use it a lot, but it's never been flashed and doubt I ever will need to. I'm a longtime Linux user too and never reinstall, just troubleshoot and fix whatever. I've had to do almost none of that with Maemo. I've installed stuff from testing and devel, but been careful and conservative.

I use modest to handle 4 accounts nicely, 3 pop 1 imap. Been much better though since I installed this:

http://talk.maemo.org/showthread.php?t=56634