i have not tried the Jstik in 8 way mode, but it would physically look the same as your u360s. due to the shape of the restrictor plate, a jstick would have a square range of motion, which could be good or bad, depending on your taste. you could always get one to try it, if you dont like it, it makes a great dedicated 4 way stick.
someone else may be able to clarify, but i believe the regular shafts on the u360 are the same length as the jstick. my friend has a ball top jstick, and i have bat top u360s, so i canot do a direct comparison though. i had the long shafts on my u360s, which were nice for bottom mounting in a 3/4" panel...however it made the throw a little too long for my taste, also, due to the extra leverage and extra weight of the shaft, the stick felt a little mushy, even with the medium springs. i recently removed the long shafts and went back to the standard shafts, still with the medium springs. they are slightly shorter than i would like, but they feel so much better. they are no loger mushy, they are fast and responsive, and the throw feels just right. i think i'll end up routing out the top of the wood and top mounting them to get the length back.
the u360s are great, but definitely get the heavier springs, they are way to soft without them. (at least the bat top version is...but that shaft is thicker, and therefore heavier....i dont know how the balltop u360s feel with the standard springs)