I used to use Dolphin HD/Mini but I too switched to Opera Mobile after the last big upgrade, it's lightyears beyond the other options.
One question for you Opera guys, is there a way to export/import your bookmarks? I'm about to upgrade to 2.2 and all my bookmarks will be blown away.
If you use Titanium Backup, it'll backup the bookmarks for you.
If you want to import bookmarks, Opera doesn't have any way to do it on the phone. You'll have to use Opera Link to sync with a desktop copy of Opera (where you can import your bookmarks to). Rather annoying but now that I have the bookmarks I want in Opera Mobile, I just Titanium Backup.
Opera Mobile is the only browser that uses the GPU and allows-in text copy and paste iOS style.
Don't know if it really uses the GPU but it's the smoothest by far of all the browsers for Android. Try going to the XDA forums with Dolphin and you'll regret it. Butter smooth with Opera Mobile.
Ever since they added flash support, Opera Mobile has become my primary browser on Android.