The company is heavily dependent on Asterisk technology. As growth continues, it will be interesting to see how scalability is dealt with.
Voip.ms has been around under that name for 3 years or so, and around under the Swiftvox name for longer.
I can't give much in the way of numbers but have the impression they are one of the larger residential vosps. Peter Sahui, from voip.ms, said they have 10,000 DIDs in use with one of their carriers, so there is that indicator of size.
Given that, hasn't the question of scalability already been answered?