It is not an empty statement to say that all of these steels are VERY GOOD. Yes, I think that it is possible to notice differences between the steels, if you pay attention to it, but all of them will serve anybodys purpose just fine. I am a steel junky and I just love to try out steels, and I have my preferences, but to really say VG-10 is better than S30V (or vice versa or ZDP-189) I wouldn't do anymore, because they are all so damn good. Its like asking: Which is the better car: Ferrari or Porsche. I mean you may have personal preferences but we are not talking about run of the mill cars nor are we talking about run of the mill steels.
My personal preferences are S30V, ZDP-189 and BG-42 (all from Spyderco). S30V, because I can get a very nice edge on it and I am less likely to "over polish" it, so the edge maintains just a tiny bit of bite (although most people would consider it already as highly polished). ZDP-189 I love because it sharpens like an HC steel. I could put an edge on ZDP-189 with both eyes closed and hands tied behind my back (well not really but you get the idea). And BG-42 proves itself more and more in my use as the greatest edgehold of them all, and running against S30V and ZDP the is REALLY saying something. Now I very much like VG-10 as well, but I prefer the other ones. ATS-55 I would rank a little behind those four. But honestly, if someone gave me a knife with ATS-55 I would not complain. And finally there is H-1 and while I don't think it beats the others in cutting/edgeholding etc. performance, the fact that the stuff is completly rust proof easily outweighs what ever slight disadvantages it might have. I holds and edge like a knife steel should and takes a very nice edge aswell. While different than the others, it ranks for me right up there with S30V, ZDP-189 and BG-42.