My girls are 6, and just starting to grow out of their toddler beds!! lol, so they're as of right now just on their crib mattress in their toddler bed. However, we have bought them all new bedroom furniture - we're not unpacking and setting it up until we move though - and we bought them a bed frame and headboard, and mattress and boxspring sets. They are really high off the ground - the set is so thick!! I'm thinking they'll do fine with it - although I'm a little worried about little Chloe, who has broken her collar bone twice just from simply falling - but they don't fall out of their little beds often.
I wanted to add, that this is the kind of bed I had growing up, and that bed stayed with me even when I moved out of my mom's house. So I'm hoping that by buying these sets for the girls we won't have to buy them new beds for a loooong time!!