In what way is this better than any of the other hosted PBX solutions out there? I don't see the novelty here. Even the "advanced" stuff, like voice mail transcription, have been standard features at virtual PBXs for years now.
Have you worked out how you compare pricingwise to the RingCentrals of the world?
Then you look at something like OpenVBX, which would be significantly cheaper ($1/month for number, 1c per minute incoming) if you don't mind setting it up.
if it is the same or better than grasshopper, you guys will do well in the smb space.