For me, it's worth it. However, we had a bad stay at Pop and didn't sleep at all - and that's all we wanted to do in the room (sleep and shower) and only could accomplish one of those things! Some vacations we spend more time at the resort than others and that trip we tried to just sleep there and it didn't go over well. Others haven't had issues sleeping there, so it's worth it to them to save money and stay.
There is a big diff IMO - in my exp, the moderates are quiet, relaxing, spread out, and resort like. Yes, you might walk a bit farther to the foodcourt but we don't like to waste time dining at a foodcourt at the hotel anyways so that doesn't matter to us. We also drive our own car to the parks if at all possible so transportation doesnt' matter to us. There are other amenities to it as well, like in the pools and such. The rooms aren't much larger than a value, either.
The values, in my exp, are loud, crowded, and motel like. LOTS of people smashed in a small spot of land - multistory, very bright, not at all relaxing or a resort feel. We did not relax at all at the value - lots of activity all the time.
So for us, no doubt we'll be staying moderate or above because we like to vacation a diff way - and we like to sleep more than 4 hours! No one but you can decide if it's worth the price diff, really. You could do a split stay and decide for yourself =)