I took a look at their complete feature set: https://voip.ms/features#features_filters

I don't like they way they've made it harder for me to see what they actually offer vs. what I offer myself (with my FreePBX VoIP client). I wish they would (maybe on a separate page) show the capabilities of their SIP trunk. E.g. Does it support SMS? Does it support video calling? Does the client require a static IP? Etc.