It depends on the mechanics of the cleaner.
The one I use is sorta midrange:
ZDAGLLC I tried the others - I bought every single one out there under 150 bucks. There are better machines that do deep gouge recovery, but for everyday scratches, especially
redbox rentals, the Simo works like a dream. If you play a lot of CDs & DVDs, this puppy works great. NO cleaner is recommended for PS3 or Blu-ray discs as the blue coating is a special filter. Polish that off and you'd get an expensive coaster.
Ones I've used before worked great, but they are made with plastic parts and start slipping after 50 cleanings. Better to buy brand new replacements than refills. Still they're good if you just have a handful of CDs/DVDs to clean.
Xinix Repair Pro Motorized CD/DVD Disc Repair/Clean Kit
Xinix Disc Repair Pro, CD DVD Repair Kit, Disc Repair kit Aware Winning Disc Repair kit
Near exact similars are:
Future Power CD Magician
Future Power - CD/DVD Magician Cleaner & Repair
Vintech VC-2000 Dr. Clean CD
Amazon.com: Vintech VC-2000 Dr. Clean CD, DVD Repair & Cleaner: Electronics
The Xinix uses chamois pads, whereas the CD Magician and Vintech use poly cloth bound on a foam support, bound by a removable plastic ring- you can save a little bit by cutting circles of thin, strong fabric for the pads and refilling the chemical with a good car polish. The Xinix is the fastest, sporting a 9V power supply. The others come with a 6V power supply and a compartment to use 4 AA batteries. The Xinix has a "Repair" "Clean" and Eject button. The "Repair" button repeats the "Clean" action 4 times, instead of having you doing it manually on the other two as they only have the "Clean" and "Eject" buttons. The clear plastic of the CD Magician is a bit brittle, the Xinix and the Vintech don't have that problem. Stick with the Xinix, it's good all around. If only they replaced the plastic spindle drive worm gear with an aluminum one, I'd use it more often than to drag out the Simo.
I always use the chemicals supplied with the Simo kits, but for stubborn scratches, I use the slightly solvent ammonia&petroleum-rich Flitz car polish.
Flitz-Polish.com | Home Yes, it stinks, but it's supposed to remove hazing off of car headlights, so it's good stuff.
the ones above work better than any of the others I've tried. Sure the Skip Dr. uses only water to work with the sandpaper wheels, but they start collecting gunk and scratch up your discs all over again. The Memorex Optifix looks like the Xinix/CD Magician/Vintech 2000, but there's no phasing of the cleaning pads, giving constant pressure. Besides the polishing pads are fake chamois foam rubber.
I bought a kit, ages ago, which was sold as Disc Master Pro 2000. It was the best one I ever had, it worked as good as the Simo does.
It was monstrous and a bit messy as it scattered a soft ring of polish when the spinning pad was first applied to the disc. Real easy to use, and took out the scratches well though. It used a washable car buffer pad set in a drill press. (see the picture above) The major part was the polishing platform. It was one square and one circular piece of black Plexiglas plastic mounted together with a small lazy Susan spinner bearing, cut so that it's centered and balanced. The center had a rubber stopper, likely a rubber table foot, cut down to fit the center of CDs/DVDs. This little platform is the main part of the Disc Doctor, and was precision made for CDs and DVDs. They also made one for laserdiscs. The CD/DVD platform was mounted on the drill press by the use of small clamps, and the platform was tilted at an angle so that the platform would rotate slowly, as the buffer pad polished the optical side of the disc. It worked great until I misplaced the handle knobs for the Harbor Freight Tools drill press. The company went under for some reason, but here's their old website:
#1 CD Repair** Disc Doctor, Inc. Home of CD Repair systems under $200
If you're on a real tight budget, go for a high-quality
car polish (not
car wax) that hasn't dried out, and a bunch of good thin cloths. Apply the polish with a cloth on the optical side in circular motions, gently rubbing throughout. Let dry to a haze. Then with a clean cloth, wipe the dried polish off radially - from the center outward. Wipe a section, turn the disc a little, find a clean spot on the cloth, and repeat. The point is to wipe against the path of common scratches. This works on most light surface scratches.
All of this personal research didn't come free, yanno.

Wish I could flash my pencil cup here, but, nope, not allowed.