Forgive my ignorance, but who owns Deadlands d20? I've seen a S15 that has it listed for Pinnacle and another that has it listed for FFG. Which is correct?
My take on D20 Deadlands is that it is a good game..at low levels. I will say that I have not played it to higher levels but what made the original deadlands great was the 1 shot with a gun/rifle/dynamite will and can kill you. At higher levels in D20 it looks like the heros laugh at someone with a gun as in DnD when you see your opponent barely can hold a sword you know that you cannot be killed by him. In Deadlands at least there is a chance that even a neopyhte with a gun/dynamite stick/etc. can hurt you badly or kill you. Much funnier IMHO.
I really thought the system was good and with a few tweaks it will be better. I also ran the first 3 adventures for Deadwest the living city type game using Deadlands D20 rules and I really, really liked the way it ran. If you all get a chance take a look at Deadwest in your area or during a Convention.
While I've never played Deadlands myself, one of my friends has shown me several of the d20 Deadland books. All I can say is that they are nice references that might make it into a d20 Gamma World game if the upcoming Gamma World d20 mini-game is as good as I hope. (I think it's the one coming after Mecha Crusade, which is the next issue.)
Deadlands meet Gamma World, Gamma World meet Deadlands.
{EDIT}
I just might have to take a look at the printed version of Darwin's World too.