CJ gives a defence boost, which will counter some of UY's debuff. This is a good thing. CJ is very low cost toggle, while jump kick is a hugely poor attack. CJ wins over jump kick.
Jump Kick not only probably has the weakest dmg out of other travel pool powers such as Air Superiorty and Flurry, its animation time can be considered as a bit lengthy.
Like MaX said, it is a low endurance costing toggle (the more toggles you have the more your opponent needs to do to knock them all off) and offers an increase in verticle jump (boost in height of jump...hurdle=boost in length of jump).
@Captain Solaris
Guild of Extreme Heroes "Strength is in Unity"
Meh avoid Jump Kick like the plague, long animation attack are very poor in your attack chain. More so that as a brute you need a steady flow of attacks to keep that fury up.
The other thing Combat Jumping is good for is jumping around, like in combat. Go figure.
I really should do something about this signature.
cool. As long as the CJ and Uyeild doesn't take out each other too much I'll prolly go for CJ.
I know of the low dam and long animation for jump kick but I can't help to feel that it is one of the coolest looking attacks in the whole game. 
An oft understated thing.
I can tell you, superspeed + hurdle just needs combat jumping. Not that I'll be able to get it. 
Making an inv brute and want SJ. Is there any point in taking CJ if I'm getting unyeilding since unyield give negative in defence and even with CJ you get a negative value? Should i instead go with jump kick which I'll prolly seldom use?
What's best?