Oh and by the way I think there are some mighty worthy companies on the list. Having SunRocket make it is logical as they are a strong player in consumer VoIP and under the radar. One might question how this company could be on the list and Vonage absent. Of course then what about Skype?
I like GrandCentral and just wrote about them yesterday so good call on this one. Empirix makes sense as well but what about Spirent and Ixia? Firsthand also makes sense as they are very strong in SIP and do good work.
There are many more I would add but hey the list is only 15 long so there obviously has to be someone left out.