FWIW over the next few weeks I will be porting the numbers I manage from voip.ms to fongo (freephoneline), dropping voip.ms, and routing all international calls through a callwithus trunk - they have the best INTL rates I've seen anywhere.
Before I had all 3 in a filter on my PBX that selected the least-cost-route for each call, but voip.ms just became redundant when CWUS is giving the same or cheaper + free toll-free calling.
I didn't do this sooner because I was still testing out freephoneline. Happy to report I've only experienced 2 short outages since I signed up this summer.
In the end no one really needs more than 2 trunks - one for free local calling and one for cheap * reliable international.