I think it is one of their better releases in their history. They really went the distance to make sure it was as clean as can be. Having tried all of the available alternatives, I still feel Opera is the best browser available. It has the most features - it is the fastest - most secure - and most user friendly of any of the major browsers available.
I've given up on opera.. its slow.. crashes and has a ton of strange issues. Hopefully 10.1 will fix it but they seem hellbent on adding more functionality (Web server built in) rather then increasig performance/rendering issues..
heck, IE 8 handles facebook/twitter better than Opera 10 and thats saying something!