Broadvox is a VoIP service provider that offers business VoIP service (SIP trunking and Virtual PBX), enterprise VoIP service (wholesale termination and origination), and broadband Internet (Go!Broadband).
Review of Broadvox GO!Anywhere SIP Trunk
Broadvox's Go! Anywhere SIP trunk is a standard SIP trunking service: you get unlimited calls to the United States, Canada, and US territories, E911 service, and several selections of phone number. You can get toll free numbers, local numbers, and international DIDs.
You will need an IP PBX in order to use this SIP trunking service.
In addition, with this Broadvox service, you should probably think about committing to a contract - you'll save a lot. Contracts with Broadvox can be up to 3 years long.
Finally, Broadvox doesn't have a restrictive fair use limit. Basically, don't do anything illegal or prohibited (auto-dialing, fax blasting, telemarketing, et al.).
Review of Broadvox Enterprise Service
Broadvox Enterprise VoIP service is like super SIP trunking. Basically, you can purchase a certain number of origination or termination minutes every month (used for calling in and calling out). Based on the volume you purchase, you'll save money over purchasing concurrent lines with Go!Anywhere and purchasing seats with a Virtual PBX.
Enterprise VoIP is a great choice for call centers and any kind of business that needs to do the things that are usually prohibited by the standard terms and conditions of a regular business VoIP line.