Have you used Safari? Automatic reading list syncing, bookmark syncing, extensions, reader, smooth html5 execution (often more smooth than even chrome), and it uses the webkit engine, and is even faster than Chrome and Firefox with some tasks. Not to mention its the fastest iOS browser. Opera is actually pretty bad at rendering pages correctly, being the only one using the Presto rendering engine.
And just to clear this up, I have all browsers on this list, an with the exception of IE, use them all very frequently.