Neo is waaay too glitchy at the moment to try RS'ing from main shops, so I can't go give it a go at the moment, but I can tell you that here in Sweden at least I've suffered no difficulty compared to RS'ing in the states. I live here in Sweden, but I'm American and visit home (Texas) every summer and play Neopets there during that time too. So, I've had the chance to RS on both sides of the pond two years in a row now and I've seen no difference in my success/fail rate at RS.
Hope that helps you a little.