Another Litter Robot owner here (we are onto our second one) and I feel it does cut down on the smell. The litter won't stay in the open part for more than 10-

Another Litter Robot owner here (we are onto our second one) and I feel it does cut down on the smell. The litter won't stay in the open part for more than 10-25 minutes and then it is cycled into the drawer which is relatively contained and has a charcoal filter on it. We have two cats and end up changing the drawer every 2-3 days. I have a friend who manages not to change the drawer for a week and I do think it starts to smell then. The main benefits are that we don't have to tend to the litter tray that often and when we do we only need to pull out the plastic trash bag, tie it up and replace with a new one. I also think it uses a lot less litter as we never have to fully change it out like you do with normal cat boxes. It's an expensive item but I think it's definitely worth it. Get a reconditioned one for $50-100 less as they are perfectly clean and they will get messy pretty quickly anyway. We pair ours with Nature's Miracle cat litter which has baking soda and other deodorizer in it.