the bubba is going to be the better pow ski its the widest ski armada make and has the smallest running surface i.e. more rocker. it is a newer version of the old ARG if you remember that? the ski they rent at retallacks. so its basically designed for bottomless pow on heli and cat ski trips.
however the magic j is not exactly narrow and if you've seen any of t-halls resent edits you'll know its just as much of a pow ski then the bubba. the magic j is a bigger jj with less taper and stiff over all. this mean it charges and is more stable at high speeds. it also will blast crud and chopped up snow better. it has more camber then bubba so it will be better on hard park. all these things making it better in variable terrain and in a resort.
so to conclude, the bubba is an out and out pow ski with more rocker and more floatation so if all you're going to be hitting is pow and you'll be skiing it at slower speeds tun get the bubba but if you want a ski that will charge more and is a bit more burly with the possibly of taking it to a resort and hitting variable terrine at high speeds then get the magic j
hope that helps dude sorry for the essay. theres also a good diagram on the armada website that shows the difference in the surface area of each ski i'll post it up here if you can't find it.