http://www.strongframes.com/material_tech/specs/
Rody says this is a bit derivative of manufacturers' claims, but still quite a useful summary I think.
Seems to me all the different tubing is 4130 chromium-molybdenum and thus all basically fairly similar, although the various manufacturers all claim theirs is the best, just as the manufacturers of soap powder do.
Far more important is whether the tube thickness and butting is suitable for your particular needs. It makes no sense for example to say '853 is light', as there are lots of heavy 853 frames around - if you want to build for strength and rigidity, you have to specify thicker tubing and it weighs more, whatever brand it is.
An Inbred, Prince Albert or Pipedream Nevis all weigh 5lbs or so, and I guess the P7 must be heading that way, as they're built for strength. The Cotic Soul, Pastey Howler and Rock Lobster 853 are all closer to 4lbs because they're built to be xc whippets.
The latest Explosif is made of Dedacciai tubing, and no doubt some say 'wow, Dedacciai, that must be light', but in fact the Kona website quotes the weight at 4.8lbs, so clearly it's built towards the strength end of the spectrum and way away from the racing end where Explosifs were in the early nineties. So the name's the same but it's really a completely different bike now from what it once was. But that's not to say that Dedacciai is heavy, but just that Kona wanted to build more of an Inbred-type bike than a Soul-type bike, that's all.