Convex9 vs Intellisys Communications

In my search for a new phone provider, I stumbled across Yiptel which is the hosted (cloud) PBX / VOIP brand by CCI. My first gripe was the fact that I had to talk to a sales team member before I started a trial. Being a small business ourselves I could appreciate that, but I do prefer the fully automated trials at some of the big players where I don't have to talk to sales until I am convinced the product is right for me. I used the free trial and was glad they offered it. The service is not reliable. I had several missed calls during my testing where callers called in, but the phones never rang. The first time this happens, I always question my network on this end (are the right ports open on the firewall for example?) However after verifying all network settings with customer support, the missed calls continued. I don't know the specifics of where Yiptel runs their service, but if you look at the locations on their website (Mesa, Denver, Bozeman, etc.) and Google the street addresses, you will see they are residential buildings! Again I can appreciate these guys are not as big as Vonage and RingCentral (that's not a bad thing, smaller businesses often mean better support!), but I wonder if they are running their backend out of residences with consumer grade WAN links? It would certainly explain the missed calls. I would not recommend this service... while email is quickly becoming our dominant communication mechanism, we cannot be missing inbound calls from customers!