Ever since opera went fully free (no ads), ive been using it. It really cant be beat.
Camstuf, what version of FF were you using? I've experienced the problem of vanishing bookmarks and I think I've heard of internet connection problem but that was back before V1.0. You cant judge software by bugs that were in the beta! V1.5 works perfectly.
Judging from the problems you had im guessing that was a long time ago and those sites that didint work either did not conform to standards or were using white lists that did not yet include FF at the time? Either way it should work on almost any site now.