I use Opera since way back and I convinced a lot of my more computer educated friends to use it to... but last years was a pain. A lot of sites did not render well on Opera 9.x and I had to use snail FireFox for them.
Opera 10 Alpha worked well dough, last half a year I used it instead of Firefox for sites that did not render correctly. 99.99% of sites I tried were rendered well and now that its status is beta I officially switched beta for my main browser. It works surprisingly good, integrated spell check is amazing and some of the old features that I had to enable/change them with editing .ini files are configurable now via GUI. And I have no idea why you folks diss Opera add-block, it works for long time as someone already mentioned, and it works good.
The only other browser I tried and was as good as Opera was Chrome, mainly because of it amazing speed and Opera failed on some Google Aps (no way of using spreadsheets with Opera 9.x).
Short story, stop dissing Opera, most of the critics here are gone with version 10 so try it first.