Although I have posted much of this at various locations on the forum, I wanted to give a final report on my experiences comparing the Litter Robot (LR) and ScoopFree (SF).
Trial Period: Twenty days each with both LR & SF
Number of cats: Two
Ages: 8 months, 18 months
SET-UP & EASE OF USE
Both boxes easy to set-up and use.
CAT USE & ADJUSTMENT
SF was easier.
Comments: Both cats used the SF without difficulty. The LR was more challenging for the younger cat. He pooped on step, etc., etc. before he came through and learned to get in, partially turn, and use. I also made a modification to the doorway that may have helped him out.
CYCLING IN
The LR cycles in 7 minutes after the cat leaves the box, cycle lasts about 2 minutes, 10 seconds;
SF cycles in at 20 minutes after cats vacate, cycle lasts about 1 minute.
NOISE
The LR was quieter in my home.
Comments: With the door closed to my laundry room, despite a cat door in it, I had difficulty detecting the LR when it cycled. The sounds with each box are different, the SF a lower tone and was easier for me to hear. The LR may have blended in with the other household sounds. I was unable to detect it at night despite sleeping near its location and trying to hear it (!) whereas I was able to detect the SF.
TRACKING
Less tracking with the SF
Comments: With the SF there was less tracking; however, this could be due more to the crystals. I have tried crystals in my hand-scoop box and there's even less tracking! So part of the difference here will also be the type of litter used.
ODOR CONTROL
No real difference
Comments: Both controlled odor great at times and lousy at times. Food fed the cats, type of litter used, and who covers what seem to make the difference here.
MAINTENANCE
SF is much simpler to maintain.
Comments: The SF is simply designed with covered parts. Its easy to maintain. The rake can get poop on it. Poop can get caught in the "home" area of the box and will need to be removed manually. But these are simple fixes. I used the uncovered box and odor does not build in it whereas this does occur in the LR. This doesn't mean that urine isn't building on the rake, etc. in the SF -- I did detect a urine odor when cleaning it. With the LR, gooped up litter can cling to the walls of the LR (can depend on litter used, as well), cats can poop and pee outside the litter covered areas and because of these and without much ventilation inside the globe, odor can build. The LR is more complicated to clean; however, after gathering my cleaning supplies, I timed myself and swiped out the inside of the LR globe in seven minutes -- this included brushing down any clinging litter, wiping out twice, drying with a small hand towel, lubricating the lining, AND the two minute cycle time! I think weekly maintenance of the inner LR globe is a key to keeping it fresh for the cats but time will tell...
LITTER CHANGES
LR used less litter.
Comments: In twenty days, I changed the crystals three times in the SF due to moisture on the bottom of the cartridge. I pushed it to 9/10 days by stirring the crystals once/day starting at day 6. With the LR, I would not have changed litter at all (I was experimenting with different litters at this point, however...) -- just add some litter once a week or so.
MECHANICAL INTEGRITY
Both boxes worked with NO mechanical or other failings throughout the trial. Very reliable.
ADAPTATIONS
I made adaptations to both boxes
Comments: With the SF, I lined the bottom of the cartridge so I could reuse it. With the LR, I created a lip on the bottom edge and up the left side of the doorway to catch any litter being kicked out by the cats and cycle it back into the globe when it rotated. I also placed a small container in the drawer to catch waste so I could dump it very easily daily.
ESTIMATED COSTS PER YEAR:
LR will likely cost less in litter, more time in maintenance.
Comments: Many different reasonably priced litters can be used with the LR. No proprietary supplies are needed. Purchasing a reusable cartridge from someone or making your own is the most cost effective way to go with the SF. Even so, crystal litter is among the most expensive. I found the Ultra Pearls crystals to be the most affordable where I live -- about $6.00/4 pounds at a local pet store. This would have made the SF doable for me whereas the other crystal litters ranged from about $8 to $10 + for 4 to 4.5 lbs.
WHAT I DECIDED.
Kept the LR
Comments: After the 20 day trials with each box, I gave the cats a 36 hour trial with the LR and SF sitting next to each other. At the end of the trial, the cats appeared to be peeing in the SF and pooping in the LR. So, I placed the SF crystals in the cats' old handscooped litter box and returned the SF to the local pet store. After all, the cats don't need an electronic box to pee in when crystals absorb the urine! I like the versatility of the LR and consider it the workhorse of the automatic boxes... it will likely last for years. The SF has yet to prove itself in this area. I also like to dump the waste more frequently and the waste is easier to remove with the LR design. The LR can be environmentally friendly when organic litters are used and disposed of thus will not harm my septic system or the environment.
End of report. Hope this proves helpful to someone.

