its really opinion and complete setup... but
spring under- has VERY little axle wrap, lower ride hight with same springs, and it has less leverage on the springs (less flex/harsher ride) no need for hysteer.
spring over- exact opposite, axle wrap, more ride hight with same springs, more leverage as the axle is pushing spring rather the pulling ect.

however from riding in vehicles with either, I don't really notice the ride being different, or the flex. just axle wrap, almost not the with it spring under. but its all opinion and complete setup...

sorry not trying to hyjack. nice new rig. looks like it it a lot more capable then the xj based on the pics. I wish the XJ had a frame and open top... I think it was a good upgrade.

 

Overeasy I finally got a chance to wheel on the pitbulls and HOLY_______ they are damn good wheeling tires. Wheeled threw a lot of mud and slick dirt then played around on some rocks never had an issue with the tires and they helped me a few times getting used to the clutch and wheeling a 5 speed. I highly recommend them for a wheeling/trail tire.

Over all I don't miss the XJ at all the YJ is a much better wheeling rig as is for what I like to do. I just need a little bit more seat time with the 5 speed.

 

Thanks man, good to hear another good review! Glad you're liking it, I also prefer a 5 speed for wheeling. (personal preference though) Looking forward to more pics and stories coming out of this thread!