I am presently using it. I have connected with a significant portion of
   the network. I find it is largely inert.
   The software is not without flaws. It's design is monolithic, causing
   any error to crash the entire system. Plugins increase the fatal error
   surface, attack surface and functionality.
   The greatest problem with plugins is that I'm never sure how they deal
   with my anonymity.
   I think Retroshare could well be replaced by something alike Tor, but
   not Tor, then to have some quantity of programs connect to it to do
   interesting things. That makes it more confusing that it exists,
   because Tor does already too.
   So, why use Retroshare instead of a Tor hidden service with standard
   chat relay? Because Tor is a target and RetroShare is not. And because
   Retroshare actually does a lot more than relay chat.
   I do not have a solid recommendation. I use it for curiosity reasons
   now. Although occasionally stimulating in it's novelty I find it unfit
   technically and practically for critical work. It still seems to be the
   best tool for the job, not unlike the rock-and-stick tools were the
   best for cutting lumber in days long past.
   2013/11/16 rysiek <[1]rysiek@hackerspace.pl>

     inb4 "Java suxxorz" -- yes, I tend to hold that view myself; hoever,
     if
     RetroShare is a workable solution, we can simply add
     C++/Python/Whatever
     implementations later, right?

   I think the implementation is messy. It might be less then normally
   convenient to add other implementations.

References

   1. mailto:rysiek@hackerspace.pl