I'm still on 0.7 as I'm waiting for the debian package to be released, but I spoke to a guy today who says that firefox is quite buggy compared to firebird 0.7 (he does have a tendency to exagerate though).
i actually think mozilla is better, spyware and shit doesn't install it'self on my computer and firebird/firefox has mroe features, but yes, Slimbrowser is good for the IE only user
Plus with mozilla/firefox you use actual web-standards-compliant renderers instead of this IE shit which just encourages webmasters to use random IE-only styles and scripts.