We missed Marshmellow, didn't see him at all, but we had a great time in the snow fest area and meeting Olaf! The pager system was fantastic and didn't seem like it was happening on Saturday/Sunday as the sign on the Olaf side said 80 minutes (regular snow play was 30). But Monday we went over and there was no time listed at Olaf, so I asked and they said it was just a wait for a pager, not bad at all. We played, sled, etc. We did get a talking to about my little throwing snow, which is hard to stop them from doing when they're 3 and never see snow.
After having such a horrible experience back in November trying to see Anna and Elsa in Fantasyland, I cannot speak highly enough about our experience with all the Frozen Fun stuff this last weekend. It was such an easy and smooth process and my daughter LOVED it.