After reading other reviews, I just have to put in a good word for moon sand. We have two sets, including this one, and it is loved by all in our household.
Yes, it can get messy and come out of the container... If it falls to the floor, it vacuums right up since it is a relatively dry substance. Have you tried to vacuum up Play Doh? It gums up the sweeper if it's wet and gets permanently pressed in the carpet if it's dry, so I'll take "easy to clean" moon sand anyday. If it gets on the table, I just use a dry paper towel to wipe it off the side and put it back in the container, since the table is clean. We have very little waste. (You could always put a clean mat under it during play if overflow is a concern.)
Moon sand never dries out, honestly. Our first set moved across 8 states from last year, sat in hot storage for a few months and is still soft and supple. (It was also one of the first toys the kids asked to play with) Playdoh is rock hard overnight if left unattended.
Moon sand is very pliable, however it does take a mild amount of pressure to compress it to mold it. We have found that 4 to 5 year olds in play group had no trouble, and we didn't have problems getting it out of molds like other sticky doughs.
Yes, the multiple colored sand did mix together, my kids did that on purpose to "make it pretty", however I always found a wad of multi colored dough when the children played with different colors of dough,anyway. They don't mind, so why should I?
The biggest factor of all and the biggest reason to ever buy a toy... THE CHILDREN HAVE A GREAT TIME WITH THIS! Isn't that what it's all about? I'll buy any toy that has a few perceived small cons that I know they will love compared to an easy to maintain toy that will sit on the shelf and bring no joy at all. I find that almost every toy has clean up, and this one has less than most for me. I respect that it may not be for the other reviewers, maybe perhaps not for "toddler" ages? I can honestly say for our household of 4 and up it is absolutely a favorite requested toy. Visitors that come and play all love it too. Enjoy!