I really don't think there is a great difference in the two. If you have waterfield on the way i wouldn't go out and bother to order the RCM one. I bet if I shook the crap out of my waterfield that I could get some more larger glitter to come out, LOL. It's a tad more in the RCM one, but that is also something that could easily vary from batch to batch, how much glitter they put in.
Ok I feel better. I fell in love with waterfield when I saw your Christmas mani. I thought it had a ton of bling but assumed you used two coats? If so, that'll work for me.
