Today I installed Opera 10.50 beta on my Windows XP, and it looks great and seem to work well. Of course I had to do all kinds of tweaks because I'm using it next to Opera 10.10. Luckily almost everything was very easy to fix thanks to Tamil's guide: How to transfer all settings from one Opera installation to another?. …
While writing this I noticed a little problems when adding links into post, but nothing serious. I had to double click OK-button for some reason, and I could not add link for selected text like I could on Opera 10.10.
Widgets are not running independently, and I'm not yet sure if it's a good or bad thing. I liked it on Opera 10.10, when closing browser also closed all the Widgets. Now I have to see if I can just close computer without closing all widgets first one by one.
UPDATE 12 Feb 2010: Honeymoon is over 😀 Today, when I started PC and Opera 10.50, the Z1-TEN skin was no longer looking good if I opened side panels. And now I'm forced to start each widget one by one, which is not so funny after all. Using standard skin on 10.50, or 10.10 till I find time to report problems on appropriate forums.
I also notice I had build 3247, so I upgraded to build 3248. Now I can add the link to selected text on editors, but it still requires double clicking.
EDIT: Testing editing on Opera 10.60