There only as good as the individual. Ive seen good and bad jobs done in the past. I think you'd be able to tell more on darker cars, as ive seen a few stonechips on bonnets done and you can see small rings around where the chip was.

I dont think id use them on the escos especially on a panal, although i was going to use them for a couple of chips but on the front bumper but decided against it and left it. Its probably going to cost about half as much as getting to painted properly, so may as well pay the extra for a proper job in my opinion.