FlatNetwork

iCore - Don't put them on a short list
Data circuit price gouging - $100 per month uplift on a Comcast circuit. That means you will pay $100 more to have iCore bill you for the circuit. Should it fail, iCore will work with Comcast to restore it, but here is the catch - they need to talk to your to gain access to your site! Back and forth with a middleman.
Support - During business hours a person will answer the phone. Just don't expect them to know anything about VoIP. They will "write down" all your questions and when support attempts to translate them, they have to call and first ask you to clarify things (If they call at all).
Account reps don't track client requests in any kind of a system. If your rep gets sick, goes on vacation, gets replaced, or gets lazy, nobody at iCore knows you need something. Not even your reps' supervisor.
The contracts are bulletproof and difficult to break without exorbitant fees.
Based on other reviews here, we have concerns about getting our dedicated numbers back when we do leave (Which will happen as soon as the contract is up).