I’ve just updated to the latest Opera 10 Beta. I must say I’m very impressed. Loads quick, both start-up and page loading times. Looks nice and adding widgets (like the FF plugins) is straightforward and quick.
Just have in mind that, like Opera states:
This is a beta version of Opera. Please use it only on properly backed-up computers. It is a stability release and records additions, fixes, and improvements made to Opera 10.0 beta 2. For your reference, please see the previous Opera 10.0 beta 2 for Windows changelog which was released on July 16, 2009.
I haven’t had any issues but others definitely had (thus the stability update). To try it on yourself simply visit their “next” download section.