I am an existing customer. Can't post a full review yet, because I have only been there a short time, almost a month now. But I can share with you my early impressions.
1. Support has been excellent. They helped me with the initial modernbill and kayako setup. (Kayako should have been a piece of cake but the install docs were a bit out of whack) I heard great things about modernbill, but what held me back was the complexity of mb install and configuration. There were problems (on modernbill's end) integrating modernbill with the directadmin module, and they coordinated with modernbill themselves, and got it straightened out.
2. Servers have been reliable. I believe they have servers at the planet and NAC, and have had no problems in that regard.
3. Support has been very responsive. Any questions I have had were answered in a very timely and thorough manner. They are very knowledgeable in server management and security.
That's about all I can share with you at this time. I'm happy I choose them and am very confident they will be here for the long haul. I have absolutely no concerns putting clients on their servers.