Indeed, and I love the cards, any reason you chose the 330gsm over the 310?
Heavier stocks in the 330 gsm range are more like a casino-grade paper. USPC used to use 310 for Bicycle standard decks, though these days they don't measure their stocks in grams per square meter - they measure them by a range of caliper thickness, or so I've been told. Current information changes like the weather, however...
I can't speak to WJPC's quality. I know that Noir Arts, what little I've seen from them, was inferior. The printing is OK but the quality of the paper and coating was lacking and the cards had a pressure lip around the edge, a sign that they punch them a few decks at a time through the die cutter instead of individual cards, one at a time. MPC's not the best out there, but they're not bad for what they offer and I know many, many artists that use them for prototype decks regardless of who they're printing with in the end.