I took JJJ for 2 years a while back, and whilst I respect all the pro's of it as a self-defense martial art, I think the Sensei of the dojo is the true test of whether it's an effective Martial Art
I got extremely frustrated with always having to tell my opponent/partner how I was going to attack them, and then always having to attack in the same manner (always stepping to punch, always swinging your leg up to kick etc.), as I simply felt it wasn't realistic by any means.
However, my brother does JJJ in London, and is loving every minuet of it. From the sounds of things, he's getting a better quality education for his money. Now on the rare occasions we spar, his throws and counters are quite effective (but no match for Muay Thai & some sloppy wrestling Mwahahahahah)
If brute force doesn't work, you simply haven't used enough!