Yeah, I am biased, but there are other reasons to go 14B also. You have many more options for width too. Van width, duelly width and full width. And the 30 spline thing.... remember that the spline angle is different and therfore fewer splines, but I think very close in diameter at the splines for both axles. Yes there are fewer locker options, but without rear steer what do you need to unlock for any ways? Call six states and ask how many 14B shafts they have seen break.
The 14B is WAY EASY to set up gears in too! Also the bearings spin on the Dana 70(carrier bearings) and the tubes rotate on the 14B. Both are heavy. I don't know about disk brakes on the D-70 but the disks on a 14B are bolt on easy. You have to get rid of the yoke and go to a U-bolt yoke on the 14B or the rocks will chew up the bolts. (ask me how I know).
Either axle will do what you need and that's give you brute strength and full-float reliability. Really it's your call. I have a duelly width 14B set up for 4 link if you want to buy it. Disk brakes, BTF truss, set up for coil over, NEW YOKE*, 4.88 gears, Detriot locker, track of about 64", 8 lug of course. Oh, and shaved