There was an article in Cycling Weekly about these a few years back - then made or marketed by Bioracer. The author reckoned the best result was a mixture of the Reskin patch and chamois cream; the "test" was conducted on a turbo for "about an hour" if I recall correctly, and raved about them.
I tried some on the basis of that article and found them pretty well useless in the world of "real cycling". Using them with cream was utterly hopeless, as you might well expect, since the patch quickly came detached from the skin and just moved away from the required area. I tried them again, in the proper way, i.e. applying them to totally dry skin but once again I found that over a period of several hours riding, I sweated enough to loosen the patch and it again just rucked up causing more discomfort than I'd have suffered "au natural". I also found it difficult to get the patch applied so that it went on without a crease in it from the off, but that may just have been because I didn't take enough care over the task.
So they didn't work at all for me and I have the feeling that if they were any good, the whole cycling world would be singing their praises by now, since saddle soreness is a pretty common complaint.
In the interests of objectivity however, I would have to add one thing. A couple of years ago, at the annual Cycle Show, there was a stand on which a rider was riding continuously throughout the exhibition for charity. This was the "hard-as-nails" guy (Jim Rees? I may have the name wrong) who'd twice ridden the RAAM and who surely would know a thing or two about long distance riding. He swore by these Reskin patches and when I recounted my failure with them, confirmed that yes, you did have to be meticulous about applying them properly to clean dry, grease free skin but that once you'd got the hang of it, they were really beneficial for long hours in the saddle. For what it's worth, he said he didn't use a Brooks but did the RAAMS on one of those split saddle with a droop snout a la Mark what's 'is name, the round-the-world guy.
So on balance I'd say save your money unless you're really suffering and are ready to try anything and are prepared to persevere.
