Combatives in General
Rise of Krav Maga is a part of a martial arts trend nowadays to proclaims combatives as "the next best thing" (remember Karate, Kung Fu, Tae Kwon Do, Brazilian Jiu-Jitsu, Tae-Bo, what have you, in roughly chronological order?).
Combatives are excellent for bringing up raw recruits with minimal unarmed training quickly up to speed on basic unarmed self-defense methods that mostly work well. However, it is a part of the equation rather than a whole solution to unarmed self-defense.
For realistic self-defense training, there must first be an appreciation for the effects of weapons (firearms, blades, pipes, scissors, chairs, etc.). Systems such as Jeet Kune Do and Kali tend to excel there.
As for realistic UNARMED self-defense training, there should be, at minimum, three things that are achieved by such training:
1. Physical attribute improvements (Karl Gotch always said that "conditioning is the best catch" and Don Draeger pioneered the use of weight training for Judoka). Too many folks fall for "superior technique only can overcome strength difference" trap - there is some truth to it, but not enough to fall back on reliably in all situations.
2. Realistic techniques for ALL ranges of unarmed combat. No countering one punch with a duck and ten counter techniques or catching the punching arm by the wrist and wrist-lock throwing.
3. Dynamic training (free-sparring or Randori) to the extent possible (again in all ranges) while preserving the margin of safety for the trainees. This is very important as static, "I-hit-you-then-you-do-this" type ONLY training does not prepare the practitioner for dynamic, unexpected and "fast-and-furious" reality of actual physical encounters. Many Aikido dojos, for example, delude themselves in this regard (not to say that Aikido is useless - it has some marvelous techniques for weapon retention and builds attributes like crazy - but that's another story). Of course, one can NEVER be 100% realistic, but some realism through sparring is better than none. No, the UFC is not realistic, but it is heck of a lot more realistic than Tae Kwon Do foot-tag competitions or kickboxing matches, or for that matter, no sparring/dynamic training at all.
Does Krav Maga (or any combative) fulfill all three? No - one, maybe two, but not all three. But then again, what system really does? Few, if any. Brazilian Jiu-Jitsu (which I practice and love)also covers one or maybe two aspects at best. Naturally, some are better than others (I wouldn't for the life of me recommend Tae Kwon Do, for example, as a realistic unarmed self-defense system).
Lastly, it should be noted that with any system, there must be constant practice. It's been scientifically demonstrated that muscle memory takes a minimum of 1,000 repetitions to achieve properly. Practicing some combative type moves or some Jiu-Jitsu "tricks" a few hours isn't going to do anyone any good.
If one is serious about learning unarmed self-defense, it must really invove a lifestyle change. But then again, it's good for your health (generally) anyway - so why not do it?
Otherwise, don't expect to be a couch potato, go learn Krav Maga (or anything) for a few hours and be falsely confident about one's ability to handle onself in dicey situations. If time is an issue (that is if you are too busy to work out at all), spend the time to learn to operate better equalizers (firearms, for example) and hope to God that you never drop it, lose it, struggle for it or generally have it unavailable (as several cases have demonstrated in the pages of "American Rifleman").
BTW, I personally like Brazilian Jiu-Jitsu, NOT because I am deluded enough to think that it's THE SYSTEM and NOT because I want to flop to the ground to fend off attackers, but because 1) it's fun for me and 2) because it deals with one situation in which I cannot use my track-and-field skills to run away like a bat-out-hell to "evade" the situation - when I am FORCED to the ground (lose mobility) with no other weapon. My goal is not to get arm locks or foot locks. My goal is to use whatever method possible (including arm locks or foot locks or anything else) as a means to HELP ME reverse the situation, get up and take off in a hurry - which is the real end.
Skorzeny