I had a great experience with Socious
We initially launched Socious back in 2010 and it was our first community platform. We had been using a basic mailman listserv and the time had come for us to provide our members with a little bit better way of communicating and collaborating.
We had some different kinds of requests because of the makup of our organization and they were incredibly accomodating. Their customer service and implementation team couldn't have been more flexible and helpful during the process. It took us almost a year to implement but that was our fault and they were really understanding about our delays.
My main issue (as well as some of our board members and members) was that changes made to profiles and working groups did not synch immediately and would need to wait till overnight in order for changes to be reflected. That was big for us and while it had more to do with our API than the platform, the board always saw this as something that hampered our member's engagement. As a first platform it was great for us and really helped many of our WGs manage their documents.
We changed to HigherLogic in 2016 mostly because of their ability to have data sync more often and because of their ability to manage bi-directional data flow using ActivitySync. We were thrilled to hear that Socious had been acquired by HL. Hope to see the best of both platforms come together in the near future.