To answer your question the only thing that stands out on Resin over diecast is Paint quality (sometimes) and packaging/presentation. O and the really nice ones, like BBR cost more than pretty much all diecast except CMC. Resin is just cheaper to produce, and quicker to produce, because of that ability to get the models out quickly they can charge a premium to over zealous collectors. I do not look down on Resin models or collectors who buy Resin models, but personally they just do not have the same charm for me, I have about 1 resin for every 100 models in my collection and it will likely stay that way. Every now and then I will get one, but I largely ignore them. There was usually plenty of good diecast models to keep me satisfied.