Used these for my 8 string and the 1,14 version for my 7 string, but eventually moved exclusively to 1,5 because they simply felt better. If you're moving to these from a thinner pick, you'll probably get more time out of these since there's more material to dig through. There are no nubs or grit on the surface to help grip, but the material itself has a rough feel, so that helps. It does wear off somewhat quick, though.
I've since moved on to hand-made 4mm plectrums, and they are such an improvement to any machine made picks I've tried, I don't really use the GG's anymore. But if you want a good standard 1,5 pick you can afford to throw away, you can't go wrong with these.
+cheap
+material is rough enough to keep your grip
+good color choice (not bright purple like some 1,5)
-lack of textured surface
-material loses grip as it ages