Re: aikido vs jiu-jitsu
IMHO, trying to choke someone while your mounted is not a good option. You need to escape. It is pretty hard to submit someone while they control your hips/center and the fight.
also, aikido contains elements of jujutsu since it was derived from it, but the fact that it is a DO art now, I would argue that Aikido is not jujutsu, and jujutsu is not aikido, they are two separate arts. If it were the case that aikido was jujutsu, then I wouldn't get mopped up by jujutsu guys all day long while learning jujutsu!