It is a good browser, and the fastest out there. Problem with Opera is that it has never been promoted much and hence its usage is limited to nerds in Europe pretty much. But compared to IE and Safari, Opera is much better and safer.
"To waste, to destroy, our natural resources, to skin and exhaust the land instead of using it so as to increase its usefulness, will result in undermining in the days of our children the very prosperity which we ought by rights to hand down to them."~ Theodore Roosevelt (Message to Congress, Dec. 3, 1907)
On my Karmic Koala OS i use Firefox.
On Windows i use Chrome.