I have been reading about it... and it IS different. Some like it...some don't. I almost always wait for weeks until I see the fallout and opinions before making major changes to browsers.
One advantage of Opera is that it easily allows installing new versions side-by-side with older ones, and allowing easy comparison. Firefox makes it a LOT more difficult to do this, as it 'seeks' out old copies and updates them, whether you planned to or not.
   I like Firefox, but I will wait.........