I use two hooded trays for my 4 cats and they work a treat. With regards to the smell - I think it partly depends on what you feed them. My cats don't get meat as two of them get tummy problems (and then they are very stinky ) Mine get Royal Canin and they don't smell too bad at all. I take out all poops and wees first thing in the morning and last thing at night and you really can't smell them at all