I've been using Mozilla 1.0 and its OK but it has some annoying bugs and doesn't do antialiased text. It also insists on using its own mail client rather than the one I actually use. It is kinda snappy though.
Omniweb is not bad but its a little pokey and has some issues with javascript and java applets.
Exploiter is just crappy. It only accepts every other click (why highlight the link if you're not going to follow it). OTOH, it is the most likely to work with weird sites that use questionable code.
Opera - puleezze - still very buggy and lame.
iCab - nice little company with interesting ideas but not fixing bugs fast enough.
But this thing - gecko layout with quartz rendering and cocoa UI - for a 0.4 release its a rock and its snappy. I'm sold. I've got a new primary browser.
Get it at [link|http://www.mozilla.org|http://www.mozilla.org] - its the top news item today. Chimera is the project name, the app calls itself Navigator.