Krav is very effective because it's very practical and open to real life situations. With Krav it's not for sport which is why there are no competitions for it. You can use it however in MMA competitions although again you can't use it to full force. Rear elbows aren't allowed in most MMA competitions as well as groin, and throat strikes and eye gauges which are all taught in Krav Maga. We also train with how to disarm guns, knives, sticks in all types of situations as well like kneeling down with your arms behind your head if your attacker instructed you to as well as being in a car and someone comes to attack you with a gun. It's very all around. I've been doing it for about 2 years now and I've still only scratched the surface of it.
On another note I am also studying BJJ now as well and want to get into competitions. What I noticed is that Krav's ground game is similar to BJJ(though not as extensive - which again I wouldn't fully know since I just started BJJ last night) which makes sense since Krav takes everything that is practical and puts it to good use. Even in there main headquarters for the US in LA they have BJJ classes.
On another note I am also studying BJJ now as well and want to get into competitions. What I noticed is that Krav's ground game is similar to BJJ(though not as extensive - which again I wouldn't fully know since I just started BJJ last night) which makes sense since Krav takes everything that is practical and puts it to good use. Even in there main headquarters for the US in LA they have BJJ classes.