I tried them out. Seems to be just like any other ANR headset out there. But their big thing is "The Button". It prompts the ANR to recompute based on the current sound environment. Sounds like a gimmic to me. Isn't ANR always adjusting to the outside noise? In any case, there wasn't that big of a difference to sway me. I am primarily looking at long term value and I doubt they will resell as well as a Bose set would.
 
I picked up a set at Oshkosh. I've been flying the past year or so with the 1st generation Zulu. I must have a big head, as I never could really get the Zulu adjusted big enough to fit my head well. The S1, seems to go a bit bigger. Additionally, I really liked the iphone controls built into the battery box on the S1. In the plane I am flying (Cessna 150 while I finish up my 7A) my iPhone seems to want to wonder around the cockpit inflight...now I can start a playlist before departure and put the iPhone in my bag.

Anyway....my $0.02...