I'm using Chrome. If you're on the dev channel, you can unlock themes and extensions. There is an adblock service for it. It uses adblock's servers as well. As for the GUI, I have found it to be a lot better than the alternatives. It's a lot more minimal, which I love. The status bar is better. The tab placement is better. A single search/address bar is better. All imo, obviously.
Either way, it's a crape ton faster.