@cratte I use several browsers. Opera is currently my default but I was along-time Firefox user. At this point Firefox's auto-complete is still superior to all competitors. It's difficult to explain but basically everyone needs to copy Firefox! It is one of the key features that kept me glued to Firefox for years.
Opera's implementation is not too bad but still not as good as Firefox's. but now the other features of Opera have tipped the balance, hence why Opera is now my default.