I'm seeing a lot more interaction and conversation on Google +.
Twitter - No activity
Flickr - 66 views
My flickr photos get more activity when I tweet them out. When I post to flickr, from Instagram, the Instagram image is the one that gets tweeted out.
Facebook - Oops. Didn't post on Facebook while on vacation. Just posted. Let's see what activity this photo gets. Update: 5 likes.
Google + - +17, 4 shares, 12 comments
Not included in the Boston Herald article about interaction on Facebook vs. Google were my thoughts on Instagram.
I had the most fun on vacation using Instagram and seeing the immediate feedback of likes and comments on photos from friends.