Now we have stayed at both and LOVE BOTH resorts.
Like the first response said, if you are going to spend some time at the resort, then POR is WORTH the extra money. You really can (and we have) spend an entire day at the resort and use all the amentities. (i.e. Take a boat to downtown disney, rent a boat or two and ride down the river, enjoy the wonderful pool, ride a bike or two and enjoy the resort, see yee-haw Bob ( A MUST DO!!!) enjoy the nice food court, or take the 5 minute walk and visit French Quarters.
Now I see you have stayed at All-stars, so you know what you would be getting into with pop, all the cvalues are very similar, POP is just better themed and has a much better food court then the all-stars. (plus you can take a walk accross the bridge and visit the new Art of animation resort.
If you haven't done POR once and are going going to spend some time at resort, keep that ressie and enjoy it.
On a side note, If money is a concern have you thought about just getting one room at POR. they have rooms with one of those pull out beds to sleep five. Now with three adults that would be alittle cramped. But it would save the money. just a thought.
Either way you can not go wrong, enjoy your trip!!1