I have bought a couple of their smaller items through their eBay shop and had no issues. The casting is very nice and the parts look great. I assume their larger conversion sets are just as nice. I would go for it.

I have done two of their T-80 conversions.I bought direct from their web site. Had a few issues, but they solved without hesitation and that is a good indication, problems occur in life its how we solve them that matters.
Quality, its reasonable, the two I built, one in progress actually, have basically large pieces so a very easy and quick build but the expense of suoer detail, and thats fine with me. Both had a couple of large casting holes, but easily fixed. Instructions are a bit on weak side but they answer emails with photos etc very rapidly. I'd recommend if just for their uniqueness but Ive hesitated on some of their large kits as they do need some work on your part and so decided to wait and see if it becomes available in plastic.