I had a decent-sized forum with
www.site5.com for a few months and had no problems with speed and few problems with downtime...granted, they are a
huge host, so I'm sure that some of their servers are bogged down, and that just may be luck of the draw. My experience, however, was wonderful.
Good luck with your search....Sorry to hear that things aren't working out with ASO, as I've heard good things about them.