Facebook owns all the content you put there. On Google+ you own the content and they just host it. All that is fine, because you agree to the terms and for the average user it is an easy way to show your photos to friends, family, and even to the whole world if you want.
What I don’t like is that for every social media site you have to upload the pictures and if they’re public they get scattered and repeated throughout the web. If you invested a lot of time into arranging your photos into albums and care about the comments left by your friends, it will be harder to abandon that particular social media site, and while the end of facebook seems imposible in the near future, the history has a tendency of repeating itself, as many impossible-to-fall sites have dissapeared from relevancy.
Another thing that comes into mind is the quality of the uploaded pictures. On facebook, in the beginning the uploaded images were resized to a width of 604 px, then later that changed to 720 px, and up to some six months ago facebook started to support images of up to 2048 px. Now I have many photos I care about that are 604 and 720 px wide and I’d like to upload the full sized ones but I can’t. I mean I can reupload the larger images but then I’d lose all the social life they have – the comments. And that’s what matters the most there, isn’t it? The social interactions between people those photos engaged.
That’s why I’ve stopped relying on facebook for anything other than what it does best: engaging with friends and family, and everything there is small talk.
Another thought, P.S. if you wish:
It’s great that non-technical people can upload pictures of their lives, but what if you want to own your content? I’d love if I could have all my pictures on one place and all the social media sites and services could pull that info to populate albums on their sites with some universal API, and the comments and social reactions would be registered in this one place.
The problem with that approach is: who would be the authority to hold those photos? You could chose a service or do it on your server by installing some script.