There are only 5 VRS providers which makes it easier for you to try and check each one before port number with one of them.
Sorenson
Purple
ZVRS
Convo
CAAGVRS
Top of list being the largest and well established VRS provider down to the bottom that is in infancy stage.
Only top 2 provided stand alone Videophone, the rest is software based application.
This is pure personal opinion of mine. I stick with Sorenson, due to video quality. I have test several times and always end up seeing that Sorenson has the minimum issues with Video quality of all. Purple used to be suck with Video quality, and they have improved so far but has not matched Sorenson yet.
As for ZVRS, I don't like their business approach however there are few features that they offer was rather interesting and likeable.
I am not sure about CONVO, and I wouldn't bother CAAGVRS.
So, you DO have opportunity apply each VRS provider and get 10 digit local number from them temporarily and test each of them. Once you find one that fits your lifestyle and needs, then port your number with them. So, please do not take my personal opinion to make decision over who would be your next default VRS provider. So at least you have 5 to check out rather than 50 VRS providers back then (3 years ago), boy what an headache!
why is this thread in this section? im trying to get info on good vrs company to port my number over to.