It was a hit! The girls played in it all afternoon and into the evening (so much, we actually delayed bathtime by two hours). We kept it up overnight as it was quite warm and they were so happy to see it was still there in the morning.
In fact, we were all in it this afternoon, with a pile of pillows and cushions, Nick and I ready for an afternoon nap and we were hoping the girls would oblige us. However, the girls were so excited and had other plans, namely a tea party. So while I didn't quite get the sleep I so desired, it was very relaxing and cozy.