What versions of the browsers were you using, Martin? Bear in mind that even O2 is now pretty much officially out of date now that O3 is arriving, and FF and NetSurf are updated regularly.
The issues with Flash and other similar technologies are *not* a RISC OS browser issue, but a problem with lack of up to date plugins. In that sense, NetSurf and FF have another edge over O2 as they can use newer plugins when they become available, rather than be stuck with O2's built-in ones.
Oregano2 doesn't get a look-in here. Guess I've been spoiled by the speed of NS (and FF under Windows), but If it loads by accident I'll have banished it from my iconbar before it's even finished loading - which isn't a hard thing to achieve! (And usually invokes a nasty-looking bug too).