We have the trays with lids and doors. They keep most smells contained and the litter doesn't track too far. If you can find an old piece of carpet or a doormat, it's worth putting it in front of the door as it'll collect most of the litter.
We go for Catsan as it doesn't have it's own aroma and (more importantly) we can buy it at the local supermarket.
Food will make a big difference on the smell. Apparently some of the "sloppier" foods can get licked up without the cats having to chew and thus not getting fully broken down before they're passed, resulting in bad smells. When our two went onto a raw diet, the smell (or lack thereof) of the poos was the first thing we noticed, amazing!