NOTE:
I didn't include the LitterFree (LF) because it is no longer being produced, and I personally despise EBay. Check out the LitterFree forum if you want more info on it.
DISCLAIMER:
I have not personally used any of these products. I've just consolidated information about them from these forums. I've tried to represent the majority opinion on each product, but there are people who hate/love every box (Except maybe the Perrforma). If you disagree, or think an update is needed, post and i MIGHT update. Also, feel free to re-post this anywhere or edit it as you like. Just give me some credit, OK?
Omega Paw (OP) $25-30-Regular, $35 Large (Most recommend large)

Pros
+ Seems to work fairly well
+ Rocking the unit cleans it, just empty the tray
+ Very Cheap
+ Cats that use covered boxes use it
+ Masks smell well
+ Easy(er) to clean than some
+ Can use generic bags for waste
Cons
- Not automated, must still interact daily with it
- Covered litterbox (might be a + for some)
- Large
- Some report slight mechanical/cleaning problems
LitterSweep (LS) $70 Regular, $80 Ultra (Most recommend Ultra)

Pros
+ Attractive Looking
+ Easy to clean
+ Most cats adjust to it easily
+ Cheapest automated litterbox (Ultra only)
+ Can use generic bags for waste
+ Cleans 25 minutes after cat leaves, allowing waste to harden better (Ultra only)
+ Manages smell well
+ Company seems to offer replacement rake for free
Cons
- Loudest, longest clean cycle (though can be unplugged at night)
- Smallest litter area, some cats may feel cramped, especially if optional $20 cover is used, but cat may spread litter on the ground if it isn't
- Must use premium cat litter
- Rake can rust
- Tends to not get smaller waste pieces, may need to scoop every few days
- Can malfunction if too much / too little litter used, cat digs too much, etc.
- Newer product, so a shorter track record of breaking
LitterMaid (LM) $100 - LM500, $150-200 - LM950 (Longer, comes with cover and ramp)

Pros
+ Manages smells well
+ Most cats adjust to it easily
+ Some users claim that, if used carefully, very superior to regular litterbox
+ 1 Year warranty
+ Although disposable containers are expensive, can line them with bags for cheap
Cons
- Poor track record of breaking, sensor malfunctions
- Tends to jam, temperamental to proper litter level
- Difficult to clean, esp. litter rake
- Loud cleaning cycle
- Mandatory cycle after 10 minutes is too soon
- Must use premium clumping litter
- Some claim not big enough
Purrforma $150 - $250 (depending on cover, ramp, etc.)

Pros
+ You don’t have to buy it (Post in this thread if you like it!)
Cons
- Everyone on this forum says its like a more expensive LitterMaid that jams more often
- Couldn't find a positive review
Litter Robot (LR) $320

Pros
+ By far, the best rated product
+ Seems to work well more often than any other product
+ Can get away with cheaper clumping litter
+ With some skill, can modify waste bin to be very large
+ Quietest automatic box?
Cons
- Most expensive box, by far
- Many cats need to be trained to use it
- Huge
- Small waste bin, some complain of smell
- Not simple to clean (though easier than LitterMaid, and needs it less often than LitterMaid and LitterSweep)
Litter Revolution

Pros
+ Website claims to be more effective than Litter Robot, at a cheaper price
Cons
- Not available yet to use or review, check website for details
CONCLUSION
For MY kittens, I will first try the Litter Sweep Ultra. Price is good, and easy to clean is very important to me. I plan to unplug it when I sleep. It seems to work OK, but you get what you pay for. Will try to use the right amount of litter, and spray all parts with cooking spray. If it doesn't work well I'll try to return it and get the Omega Paw. If I had the money, I would get the Litter Robot, but I can't justify the price. Excited to see reviews of the Litter Revolution though!

