About Opera, I would say that most of the trouble I have experienced with it is related to javascript code, rather than java applets. Netscape 7.01 seems a bit more immune to this kind of pages.
Although it is a bit of a hassle to have more than one browser, I use Opera as my standard browser (PPRuNe works fine) and switch to Netscape or IE5.5 only when needed (less than 5% of the time).
One of the great features built in Opera is its flexibility regarding security and privacy, among which control of pop-up windows. With one click, you can select one of "refuse", "accept", "accept requested windows only" or "open in background".