Works great!  Keeps the box away from little kids and significantly reduces litter crumbs on the floor.  
I was so worried my cat wouldn't jump inside, but we left the door open for a few weeks, until she was 100% clear that was her spot.  Then I started closing the door while I was home in case she got upset and needed it opened.  She never complained and used it a few times while I was home.  Then one day I left it closed all day and she used it easily.  I think she likes the privacy in there now that she's used to it.  I use a high-sided litter box and I have a disposable piddle pad under that JUST in case she pees over the side (I don't want to ruin the cabinet), but it hasn't been an issue.