I'm stuck with using Dolphin, which isnt too bad. I can't wait to get ICS to try to default browser and Chrome.
I've used opera, dolphin, chrome, firefox, but I always come back to the default browser it truly is the best IMO.
I use iBrowser and it's great. (I think the best)
Opera is also getting better recently, but still messes up layout of many websites.
I found that Dolphin drains my battery. Even when I am not browsing, it's got some service or something running actively. Once I removed it, by battery lasted a lot longer. Using Opera Mobile, but it isn't the greatest. Has some issues.
Chrome on my Nexus 7 has one killer feature: You can access your tabs and bookmarks from other Chrome browsers.
So if I'm reading an article or watching a video on the N7, I can walk over to my computer and pull up the list of open tabs and continue reading. This is especially useful if you want to type a reply to a post on a real keyboard instead of using the touch keyboard. (or for better plugin support)