We've been going since my son was 10 (he's now 15), and we've stayed at the Poly (deluxe), POR (mod), CSR (mod), Ft. Wilderness campground (value), ASMu (value) and ASMo (value). He prefers the All Stars by a vast margin. We've also visited just about every other resort on property, and he still asks to stay at the Movies or Music every time.
I must say I was very disappointed with the Poly. For a resort that cost us THREE TIMES what the All Stars cost, we certainly did not get three times the enjoyment. The rooms are larger, but they are NOT what I would consider spacious. They are the size of an average room at a Marriott or Comfort Inn that you would rent on the outside for around $90. The room and halls smelled of mildew, and the AC was from the dinosaur period -- a far cry from the All Stars' digital temperature controls. The food court at the All Stars is also vastly superior to those at the deluxes -- WDW seems to think that if you're rich enough to stay at a deluxe, you should be eating every meal in a sit down restaurant.
All the kids I have ever been with at WDW LOVE the themeing at the All Stars. It's big, bold and colorful, and full of recognizable Disney characters.