Hi,
I just started Krav 1 month ago.
It's a very informal style compared to Kenpo, which is the only other system I'm really familiar with. You don't wear uniforms or belts at the adult level ( I suppose the kids need the belt rankings a bit more as an incentive). The beginners are Level Ones, and generally you train for 4 months before you are ready to test for the next level. Mostly when you go to class you will go to the class time scheduled for your level, but at my school there are a few mixed level classes on weekday mornings -- those are the ones I like best.
So far my experience as a beginner is that this is a workout like no other! Very cardo oriented, with pushups, squats, situps, etc. incorporated into every session. There does not appear to be any set routine, it's mixed up constantly and we train to rock music played loudly. Sort of like "cool" boot camp.
There is a definite emphasis on upper body, esp. punches, although we kick too. We've worked a lot on choke scenarios. No formal names for the techniques, no katas. I get the feeling that spontanaeity is the only set rule. We're training for survival in realistic scenarios. It is very much like Kenpo in the basic philosophy of using whatever works from a variety of other styles.
(My DH and I were watching a show on the Disc. Channel a few months back that demonstrated marial arts from around the world -- I forget the name -- and Krav Maga was on that particular episode. He's a 2nd degree black in Gyoshu Karate; his remark was, "that's the real stuff -- Okinawan". In other words, he was impressed!)
The make up of the classes seems to be about 70% male 30% female, all ages and ethnicities, including the instructors. Very friendly, egalitarian atmosphere.
Well that's all I can think of to report for now. I love KM!