What does the company do well? Phone.com is the company that you want to like, they have decent customer service and multiple options to give you a phone system for your small business. They target small companies.
What does the company not do well? The company does not have all the features that you would expect them to have and your ability to control your account is limited. In the event that they do have those features you have to request them to turn them on and your ability to control your own phone system is limited. For us they did not have the crucial features that they said they would have and kept telling us that they were going to add the features, but they never really got it to work "bug free".
What do you wish you had known about the company before using? I wish I would have known that 1) configuration options are limited, 2) you are required to contact customer support for a lot of options, and 3) the cost will increase greatly if you are not careful. It is better to implement another system like 3CX or go with Jive.com.