We have discussed the PVI product before. It has always been rock solid for me but I have never needed to call to figure anything out. I am the type that always figures everything out for myself.
So it may very well be they are unresponsive to tech support and return calls. But since I never have a problem with the product and can figure things out myself, then it has never been an issue for me.
My biggest complaint with the company is they do not give you dealer cost; if you are a small business and not ordering stacks of modulators at a time (and often). So that normally pushes me to other alternatives, since marking PVI product up above retail price causes it to not be so cheap anymore (compared to other solutions).

As mentioned, the Stellar Labs modulator does NOT support HDCP. That pretty much makes it a non-starter. All these digital HD modulators with HDMI input that do not support HDCP, are meant for digital signage. The companies that are re-branding for home use are a-holes. They know good and well the product is practically useless for that purpose without HDCP compliance.