I have close to 11,000 items personal photos and videos in there (60GB), and it is constantly growing, yet searchable. I also have a myriad of tools to back up my Flickr photos and metadata to Dropbox, which I do periodically.
People love to nitpick about it, but I still find Flickr enormously useful, and have been paying for Pro for nearly a decade. I try to be proactive and open to alternative photo services, but migrating to something else at this point seems like be a huge hassle.
I wish they didn't have old and new UI mixing though. Yahoo could definitely polish that.