We love this. Our son is 3 and has used this for a while. Regarding a previous review, yes, I'm rapidly learning that boys have a habit of missing unless carefully directed, but surely that's just a matter of training! It's a great potty as a 3 in 1. You can use it as a conventional potty, a step stool, or a toilet topper. We have used it for all 3, though mostly as a conventional potty. We like it so much that we're ordering a second one for grandparents house.
The other thing to mention is that it's easy to clean as it has a lift out part in the middle. I would happily recommend this item.