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...