I have used mine on two really contaminated cars so far. I have nothing to compare it to other than traditional detailing clay, but I do like it. First car was clear coated, second was single stage.
Much easier, IMO. Larger working area, no folding/kneading, easier to hold onto. I'm not sure about the other alternatives, but this does get kind of clogged up or needs to be cleaned to maintain its tackiness. I used a soft brush, Dawn, and warm/hot water. I tried the same with cold water because I was afraid hot water might ruin it, but cold water and soap did not work very well.
I did get some transfer onto the paint at one point, but was also probably not using it properly. I was jamming it into a corner and using a lot of pressure. Transfer came off without to much work.
The first one I did sounded crazy on the paint. Sounded like I was scrubbing a textured shower curtain with a scrub brush on the first few passes. Zip, zip, zip. I used mainly in one direction and could find no marring.