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.
There actually are not too many good providersin this space. The only I can think of off-hand are Phonebooth and Grasshopper. Most of the others are much too cumbersome.
I can name at least 2 other independent companies doing this that are low-drama and easy to set up.