Alot of people use opera because of its speed, but I use it for webdesigning.
A few days ago I read that opera was the browser for web designers, so I tried it out for a whole day and I think it was great with the cache system it has and the build in validation tool, which I really like, but I could have done the same on firefox. The problem on firefox is that you don’t really seem to know where you went wrong, as the xhtml on firefox is too passive and allows small errors whereas Opera seems to go really strict on it and you can see where you went wrong with html.

Overall Opera is good for when i am designing web pages but I prefer firefox on website browsing as the cache system on opera is quite annoying as you could be looking at some outdated page without knowing.