Virtual PBX for startup?
Shooter: Toktumi.com is another service.  I had much better luck with them than Grasshopper, FWIW.   We eventually moved on to our own platform (based on Asterisk initially, then FreeSwitch) for more flexibility and control.  RingCentral should be avoided.[We also frequently hire FreeSwitch and Asterisk consultants, if anyone on HN wants to be added to our vendor list.]