Is there a maximum number of files supported/recommended in Photos.app?
My Photos library has about 60,000 photos and about 1,600 movies. The total size is about 560GB. About 30,000 photos are uploaded to iCloud and can be browsed by all my devices and desktop machines. So far no problems and interaction is fluid. With old iPhotos it was annoyingly slow to view the library in its entirety and had to split it into yearly libraries. New Photos does not seem to slow down with library size. It's face recognition is also quite a bit better.