I got a pair for each of my children last year, they were just turned 2 and 6 then. Both loved them. The toddler had no problem keeping them on. I had them still wear them with thin socks when we went out so their heels would be warm. I actually think they stay on better than the regular crocs because of the lining.
I got both a pair for this winter too. They are very excited for the weather to turn so they can wear them. Hope this helps.