This was my first time claying my vehicle. I will say that it does what it says: I tried it on a small part of my car to test it out, and it certainly smoothes the rough, presumably contaminated surface. You can hear and feel the crunchy layer being lifted away, and the paint is returned to a like-new slickness. The process also seemed to make for a much nicer finish after waxing. Count me as another believer in the power of clay.If I were you, reading this review and wondering if this is the right purchase for your first-time claying (I must have spent several hours Googling and browsing Amazon for info; I know what you're going through), I would want to be told this: Buy a separate clay bar, and use soapy water for lubricant. Use the saved money to buy a nice bottle of car wash.At first I was hesitant to use soapy water instead of the detailer spray that came with it, but after some research I discovered that many professional detailers use soapy water (there are YouTube vids with professionals using soap suds for claying). I even did a test at first, using soapy water on one area and the detail spray on another, and the clay process worked just as well with soap (or auto shampoo, rather). Just be sure the water is very sudsy and constantly applied. I wound up using the Showtime spray to clay about half the car, and I nearly used up the entire bottle. Maybe I used too much, but I only sprayed enough to cover the surface (a 2010 Accord), and with something like this I figure too much lubricant is better than too little. Detailing spray isn't exactly expensive, but using the spray instead of soap could easily result in adding $5-$10 to the task. If it offered better performance over soapy water, that would be one thing, but it doesn't seem to.Before washing the car I tried using the spray alone as a detailer on a lightly dusty surface, and it cleaned well. I wish I had just used soapy water for the entire clay process and saved the detail spray for its original purpose. In that sense, this kit is probably a nice value along with the microfiber cloth (also pretty nice quality). I can't comment on the quality of the clay bar since it's the only one I've used. It was soft and didn't fall apart. I didn't see the huge amount of contaminants on the bar like you see in some customer photos (hardly any, really, but maybe my contaminants were of the transparent sort), but it definitely had an impact on surface smoothness.It was a good learning experience and good value considering everything it comes with. However, in the future I'll buy a separate clay bar. Mothers does sell the bar separately, also, and reviews seem to suggest its quality is competitive.