Opera v7 is by far the best browser on the market. No other browser even comes close. It's fast, small, and has loads of really handy features. The tab browsing and mouse-gestures is something I can't live without, it makes browsing so much smoother. The partial rendering (the way it starts to render the page while it's still loading it, unlike Mozilla) is by far the best of all browsers. The pop-up killer is also great. With my current setting it only opens user-requested pop-ups, and it works just great. Pop-ups are a thing of the past since I started to use Opera v7.
The adverts are just in the free version, if you register the advets will be gone. And Opera is certainly worth the small price of $39.
It would be great with a native OS4 Opera version. I would easily pay $100 for that.