It's more overwhelming than underwhelming. There are many more views now than just "photo grid" and "photo detail" and lots of annoying "smart" albums, which have more special treatments than just a grid of album photos. It feels unresponsive and I often get stuck in a view with no idea how to just get back to the camera roll. I often quit the app in frustration hoping it'll just get me back to my latest photos. Probably the most unnecessary update I've ever seen on iOS.