There are pluses to both. It kind of depends on the amenities you want. Also, you are more likely to find a discount on the POR rooms. The suites are usually excluded from discounts.
POR: better pool, pool towels, two doubles beds and a trundle, rooms may be a long walk from main building/dining, slower busing, hot tub, better in-room theming/decor, boat to DTD
ASMu: more room, two bathrooms, kids sleep on a deluxe fold out, (I haven't stayed there, but they might have to be closed up each day?), bigger bed for adults, one bus stop, more compact resort, rooms are in a good location at the resort, formica counters, theming is 'kid oriented': main pool has Donald Duck, all bus transportation
Also, at ASMu you can use the other Allstar pools, and other food courts for refillable mugs, so that gives your three choices for breakfast. Wallking between resorts is pretty close. At POR, you can share the pool with POFQ and the food court, but they are further apart if better themed. BOth have hot tubs and pool slides. POFQ has one of teh best themed pools on property -but it will take a little while to get there from POR.
Also, while granite countertops may seem insignificant, there is more over all counter space at the mods, and all the decor is more upscale. Nice wood furniture as opposed to laminate.
On the flip side, you lose a lot of time with transportation and walking around POR. It is lush, but long. the All STars offer more direct transportaion and you lose less time walking around the resort getting from place to place.