And of course, those Firefox plug-ins (AdBlock and NoScript) were written to imitate native Opera features...

I think browsers are like AV - all vendors are going to have issues from time to time, and we all need to pay attention to updates and revisions. The big test for vendors is how responsive they are to fixing problems (right now, Apple appear to be the slowest of the major browser vendors - they even make MS look good by comparison!).