I'm faced with the same problem myself. For me it's kinda a matter of cost. I have plenty of Sintra on hand, as well as kydex. I appreciate the advantage of the found part being still available. However, the cost of the squeegee and the chemical stirrer cost almost as much as the two 4X8 sheets of Sintra that I bought at the start of my build. With the exception of my back plate and collar, I've built my armor out of it and it will be a big component in my JP. So, for now, I think I'll go with the Sintra variant. Though realistically in the future I could see building the parts from the Patterson items. For my situation I'm just having to shave cost wherever I can.
good luck with your decision and there is an excellent build thread on here by the 5thHorseman for the Patterson route.