I've only used one once, and I've never used a clay bar. But the result was astonishing. The finish was like polished glass it was so smooth. And it must be easy to use, because I did it.
I used some diluted detailing spray as the lubricant and it worked well.
So I picked one up from Hslfords (£13) and had a go today. I've used clay bars in the past and been impressed but this mitt was a doddle to use and much faster. Used car was soapy warer as lube all good. As an occasional user of clay big advantage of this product is the improved feel, you really can feel the paint getting smoother. Feels quite corse at first but quickly smooths out as ontaminstes are removed.
Clay whole car, doing some panels 2-3 times 30 mins.
Never used a clay bar but used one of these mitts for the first time yesterday: brilliant. Super easy to use and turned "sandpaper" to super smooth glass in no time. I kept a hose pipe running on the panel while I clayed and it worked well. Happy face.