Most of the things I complained about have been fixed. I've tried the app on my iPad and Nexus5 and it works nicely on both. Also the web app works well in browsers I use. The default quality is good enough for me, so I enjoy the unlimited capacity offered.
Photo editing options are quite basic, but good enough for most of my uses. Synchronization has so far worked quite well. Sometimes there is a bit of delay even when devices are on same WiFi, but this has so far been so rare that it has not really bothered me. I've also seen couple of crashes on Nexus5.
Search feature is quite cool. I haven't added any metadata (apart from location) to images and search is able to recognise if the picture is about a skyscraper, cityscape, a person, cat or something else.. I haven't tagged person's names to images since I'm still slightly privacy paranoid about letting google now who is who.
I'm happy enough that Google Photos is my main image library from this point forward. I'm not going to migrate my old iPhoto library, but all new pics goes to Google by default and I will occasionally make local "backup" to iPhoto.