What is the best commenting system to use for Multisites?

WE were going to install Comments+ and add some CSS to make it a little prettier but we noticed it suggested not enabling it to use on all subsites if you were using domain mapping (which we are).

We know that many of our users on non-technical so we doubt that they would go and set up their own APPs for Twitter, Facebook and Google+.

We looked into Disqus, Livefyre, etc and they aren't multisite friendly.

What else is out that that works well and looks like it belongs in 2014?

Thanks