I like the collapse era feature, and also a quick view of how many techs have been unlocked in an era. I like leaving some of the techs locked if they aren't needed to me, and this tells me just which era(s) have some of them locked.
I don't like that picture doesn't fit the normal 100% zoom. You can drag the tech tree up and down. It doesn't impact the game, but feels erratic and a bit like unfinished product. Not something that will worry me way too much though.
Lastly on the color scheme, a drastic change from what it was. Some may like it, some may not. I am neutral with it. I especially like the drawing on collapsed canvas. That continuity of scenes is impressive.