The new version looks stunning. Like the description said, it really looks Facebook's inviter, so my users have no problems using it. It also uses "apps" of Hotmail, Google, Yahoo, Facebook, Twitter and LinkedIn, where users can login, import contacts and send messages to these services directly. This way is so much better! The industry has been using OAuth for so long, and I've tried searching for a non-Joomla solution, but they all cost hundreds of dollars. I'm so thrilled there is finally something for Joomla!
I can't emphasize how important it is to use OAuth for login. Users trust it more, because they are sending their details directly to the service provider. I've been using another invites sender, and they are using Openinviter, which uses screen scraping and is very unreliable and not secured. Everytime Facebook updates something, it breaks, but Openinviter never release fixes! It's frustrating, even though I understand there's nothing the extension developers can do. By using the services own APIs, you can be sure it won't break when they change something.
All in all I give major props to the guys at simbunch. They really got this right. The interface is so nifty. The "Invites History" is easy to use and looks fantastic. Even though I was initially worried about support, they replied about 32 hours after I posted a ticket, and I'm fine with that.