At this point we have broken out the second Littermaid catbox and are very grateful to have them.  These things are terrific.  I can say quite assuredly that a littermaid catbox looks better, smells better, and is easier to clean than any conventional catbox.

The Littermaid box works with any one of a number of clumping litters.  Sensors mounted in the sides of the box detect when the cat is in the box.  Ten minutes after the cat leaves, the box enters a cleaning cycle where an arm mounted with a rake as wide as the box slides down and through the litter, smoothing it out and scooping up the waste.  As the arm reaches the end of the box, it pushes open a waste receptacle and releases the dumps and clumps inside of it.  Then the arm retreats, closing the receptacle and smoothing out the litter.  The waste receptacle and its lid are disposable, and you can mount a carbon filter in the receptacle to cut down on the smell. (See it work.)

Our cats acclimated to the littermaids immediately.  It looks just like a catbox to them, and there was no fuss.  Although noisy when operating, the cats became used to the noise within a few days.  Just the other day, I noticed one of our kittens sitting in front of the box as it was on a cleaning cycle.  She patiently and somewhat disinterestedly waited for the box to finish cleaning, and then hopped in to do her thing.

Your cats will definitely track some litter out of this box, but the front ramp with its "doormat" help alleviate some of that.

As far as the smell goes?  For the most part, I don't smell the box.  The only times I've noticed a smell is when the cat is actually using the box, or when the box is cleaning itself (once the storage compartment opens, it can stink quite a bit until the compartment closes again.)  Changing the waste compartment before it fills to capacity defintely cuts down on that.

For nervous cats, the owner's manual suggests leaving the box switched off.  Then when you notice something in the box and the cat is not around, you simply switch it on--the boxes always run through a cleaning cycle when switched on--and switch it off again once it is clean.

They're definitely not perfect.  Occasionally clumps break up and become too small for the rake to pick up, and sometimes stuff can get lodged between the tines of the rake.  Thus, they are not entirely scoop-free, but they are far easier to maintain than a regular catbox.  I'm glad we got them, and I know our cats are too.