Krav Maga(sp) the best? Hardly.
I'm not saying it's shitty or it doesn't have some merit, but its effectiveness is suspect at best.
I'll admit that some of its striking techniques seem logical and effective as they sort of remind me what a street tailored version of Muay Thai looks like with the extensive use of knees, elbows, fists, and legs strikes. What I haven't seen from this style, however, is any sort of grappling or submission work. Any style that ignores that range of fighting CANNOT be the best.
And for your information, Krav Maga is not used by ALL U.S. special forces. In fact, Brazilian Jiu-jitsu, an art that has proved itself thousands of times in plain view no holds barred competitions is the primary art practiced by our Army Rangers.