I did KM for three years, didnt do any of the gradings but progressed along nicely and did a lot of seminars and that. I enjoyed it but the nature of it is repetition and i got bored with it eventually and gave up. You wont get taught any of the ‘offensive’ (military) side of it by a proper KM instructor it will be purely self defense and techniques to end assaults as quickly as possible (think about attacking eyes, bollocks that sort of stuff). Some people think its a bit underhand in that respect, but getting physically assaulted is rarely solved through Marquess of Queensbury rules!
Some KM instructors include boxing and kickboxing sparring elements including the rules of MMA and those sports as a secondary to the defensive techniques as well, but if you want to spar regularly, take up one of those sports. KM also teaches the mental approach to dealing with assault – which you may not get at MMA type sports as such because essentially they are sports with rules and referees (however anyone who is good at these sports will also be good in a fight generally as they are conditioned to it mentally and physically).
The final thing I would say, and the thing i really thought was good at KM, was the multiple attacker scenarios and techniques to deal with this. I say techniques because most likely you will lose but there are ways to get out of it if your skilled / confident / quick / strong or a combination of these.
Give it a go its usually pretty cheap and im sure you will get something out of it – oh and purchase a good strong ‘box’ (groin guard)!