Ring Central is a hosted VoIP solution. I've worked with clients who have used them before, and rapidly grew tired of them. Extremely feature rich apparently, but the audio quality was less than stellar, also, the customer service/tech support was horrendous. Very buggy also. We've helped organizations migrate to either Cisco or Asterisk based IP PBX solutions in many instances. ShoreTel is ok from what I've heard, not much personal experience with it however.