We used to have the turtle sand box until it the lid cracked and you couldn't shut it. Cats think of it has a wonderful oversize litter box so you have to make sure you keep it closed. Ants were also a problem. We now have the sand/water box it is the one that is a (little tykes I think)blue fish on one side and a red crab on the other w/umbrella... my kids end up with sand on both sides and the lids don't stay on well, so when it rains it ends up holding water too, but no problems with cats or ants.
My kids love playing in the sand and with both they dig the sand out on the ground as well. With the stand up table however, they aren't as messy and easier to clean off, like now with the weather being cooler. With the turtle, they buried themselves or each other so Iwould have to hose them off before I let them back in. Also the table doesn't hold as much sand and the box, so that helps with expense.
Sam's has a picnic table/sandbox combo that I kinda wish we had gotten -we ended up getting them the same picnic table and the sand table and paid more than the combo- and that sandbox looks like it has more of an edge they could sit on and play too, which might help with the burying part.
Either way, at my house, sand play is a huge winner!