I have used them...they are thinner than the insert decal sets you can purchase, and they are easier to clear over because you don't have to apply as many coats of clear to get them level with the PF...One problem that I have come across is that the water part doesn't work well with the ink! I have used krylon crystal clear, and put several coats of that on the decals before you cut them out...that usually will keep them from bleeding when you apply the clear...but not always... I have had them bleed even after applying the crystal clear. So I guess it is kind of hit or miss... but if they don't bleed they work great!!
I usually apply 2 coats of clear then sand it one time, then apply the decals...then apply a mist coat of clear to try to seal the decals...then heavier coats after that.
Phoebe