Well, my first impression is good, which is quite something considering how picky I am about skins, and being very accustomed to the classic one. So far, the big WTF? is the red cross button to close the tabs, is very small, and not well positioned, I would opt for something more akin to what it's now. Anyway, it's a WIP so it will change for the better in new revisions. Also, the sidebar activating method will be missed.
I like that the Opera guys continue to maintain (for now) the normal skin, as well as improving the native ones
. But I wonder why they decided to include it so soon, as it was theoretically slated to be included with Opera 10...