I am pretty happy with it so far. Got my pwsurface, morphloader and all my other plugins installed and working  It does render a little faster and I like the new posing plugin they included. Loads older scenes for me with no probs.
The tabs are ok. I did go in and set all my views to single for each tab and it transisitions between them much faster now, as it was dragging a little for me.  I have my interface set to classic and replaced said googley eyed female with dragon,lol. 
All in all I think it's a good thing. I had problems with 1.5 so ditching it for an upgrade was no prob for me.  
Now, if they will just change their website colors from the eye burning gray haze to something more high contrast I will be a happy camper,lol. :)