I have studied Tani-Ha Shito-Ryu (Or Shukokai as it is better known) and I can tell you it is quite useful. But trying to compare wether to study ju Jitsu or karate (in any style) is hard. You will get different things from both of them: Karate - A Basis in traditional Kicking, punchink, blocking and sweeping type things. Ju Jitsu - A basis in throwing, locking, strangling/choking and submission fighting along with grappling. I have started studying a progressive system of Ju Jitsu and it complements my many years in Karate and taught me things i never realised I needed to know! So study them both mate - Y not?!