The interface looks a lot the same. The tabs bar has been moved above the address bar ... not the way I am used to it. Thumbnail previews weren't there, and I tried with a lot of tabs too. Tab width has been lessened, probably to allow a lot more tabs to be able to fit in without the need for scrolling. Its still fast, although the left hand panel's bar is not enabled by default.
Now, for the good part! The Widgets. Safe to say, Opera is trying to make a foray into the extensions front with this. Widgets will be however completely HTML and Javascript based, or all out AJAX based. Once enabled, a small 3 button bar pops up at the right hand bottom corner, with buttons to add, remove and pin the widgets. I tried loading up two widgets, the 'Hello World' animation widget, and the 'Free Dictionary' widget. However, both of them got stuck on the screen, and showed nothing more than what was under them ... in this case, a fixed impression of the girl in the bikini on Opera's homepage. I don't know if this is because of something wrong with my computer, or something to do with Opera, but I hope they get this fixed fast, since this feature does look very promising.
I haven't given any of the others a try, because the two most hyped features disappointed me. Now I am waiting for the next call from Opera land! Hope they work in one go this time...