I did Krav Maga for about 12 months. I wanted something that would help out in the inevitable situation that I could be attacked on the street or something. The Israeli defense force use it and I found it very practical for different situations. It's not going to make you a super star in the ring or anything and it's not designed for that, it's not even used to learn how to go toe to toe with someone, basically it's used to get yourself out of a situation as quick as possible using any means possible. It'svery evolving, they don't hold to one particular style and incorporate boxing, muay thai, BJJ etc and it's progressive and always keeping upto date.
I love BJJ and rate it highly but as was pointed out on the street, it's no good if 2 or 3 blokes are looking to belt the crap out of you. Once you are on the ground you'll cop a few boots to the head by their mates. One on one, it's brilliant though.