As someone who has personally used both a P30t and an ME Super, I would go with the ME Super (did you really expect me not to recommend it? My ID is "ME Super" after all
). The shutter speed range on the ME Super goes from 4s to 1/2000 where the shutter speed range on the P30t goes from 1s to 1/1000. The P30t has a DOF preview that the ME Super lacks, and I find I don't use the program mode much, preferring the Av mode or Tv mode (both the ME Super and the P30t lack the Tv mode). Plus the ME Super can operate at 1/125 or B with no batteries. The P30t requires batteries in order to work, and has a lower flash sync speed (1/100 vs. 1/125 for the ME Super). The ME Super also allows you to use non-DX coded film (or set a film speed different from its DX coding), while the P30t does not have this feature.
Downsides to the ME Super are lack of a Programmed AE mode (which I don't use anyway) and lack of DOF preview (I do miss this) and you may need foam replaced sooner on the ME Super.
Myself I just got a PZ-20 for Christmas and have shot about half of my test roll in it. KEH has some PZ-70 panoramics for sale right now but I wanted a camera that I could manually set the film speed on and the PZ-20 has this feature but the PZ-70 does not. Other than that the feature set on the PZ-20 and PZ-70 is almost exactly the same. The PZ-20 has more features than I'll probably ever use.
Hope this helps,
ME Super