Interesting bit of info. I'm not sure if my Mediatrix device is locked, but it was indeed provided by the VoIP vendor.

What I'm thinking of doing in the next couple of days is try to find out what my usage has been for the past few months and then cost out the same usage with voip.ms rates. That will give me as clear a picture as I'm likely to get as to the monthly base-line financial benefits of switching. I already know I'll be able to do all sorts of extra cool things I can't do now, such as get additional "lines" that I can run concurrently.

Does voip.ms handle storage of voice messaging on their own servers or is that something you have to provision yourself? I noticed the Siemens phones had messaging support built-in, but I'm assuming it's the equivalent of an answering machine (being local only and therefore not necessarily accessible via another telephone or the net).