I also just noticed a significant change in the UI (user interface) for google+ and the layout of google+ photo (the old picasa album format is still there, and perhaps a bit easier to find, look for the album menu item). The layout is definitely even clean and makes better use of space. One item that seems to have drawn less discussion on the net is that the size of the free account space has been increased to 15GB (for photos greater than 2048 pixels, smaller than that you have an unlimited capacity) however this is now shared across gmail, google drive and google+. It is still a BIG increase.
One “new” feature you should try out immediately is the auto enhance, found under more actions menu item on the lightbox display for a single photo. Picasa has always had the I feel luck button as a kind of auto enhance but this a whole lot better. Google is prompting the highlight feature which supposedly “automatically” chooses the best photos from a collection for a new album. Its good but I’m not totally convinced it’s for me. See a little about these features in the google promotion video below. I haven’t had a chance to play with other new Mix, HDR, Smile, Motion or Pano features as yet.