Well, I have been using it for a few years, and I use it right now for
news browsing.
It might be because it is developed by a Norwegian company, and being a
Norwegian myself ...
But I also like the fact that it is the browser that appears to supports
most web standards around (though I notice Mozilla seems to claim the
same).
I haven't tried Mozilla firefox, but I have noticed a few threads arguing
which is the better, and what I have seen of the features in Firefox,
there isn't much new stuff compared to Opera, and in fact it seems to
implement stuff that you could use in Opera for quite some time

Then
again, I don't know how long Mozilla had these features either.
Happy coding!
Morten Wennevik [C# MVP]