I've heard it's very good. And since they actually charge for it, they can exist at a fairly low level of acceptance as long as they offer some competitive advantages (such as speed) and don't get too incompatible with too many mainstream sites.
Netscape appears to offer no such advantages. And since it generates no income, there's no longer any impetus to keep it competitive.
Personally, I want something to be competitive to IE. When Microsoft has no competition, they get sloppy. When there is a serious competitive threat, they produce much better software.
GET sloppy!?!? The ONE application that I can count on to lock my system up "tighter than a bull's ass in fly season" is good old Internet Explorer. This didn't start until Microsoft's "strategic decision" to "merge" the browser with the operating system.
I am test-driving Opera, but I can't rate it on a par with IE as far as usability goes--clunky is being kind.
I've used Windows since pre-version 1.0 (i.e. actually ran the runtime version that shipped with Micrografx "In-a-Vision"), but DAMN, Linux is looking better all the time.