I haven't stayed at PP, but I stayed at the Hyatt last year ($44 on Priceline), and we really liked it a lot. The shuttle is pretty good, I think it comes every 30 minutes or so. However, they do pick up guests at the hotels right across the street (I think there were 2-3 in the same area), but it doesn't take that long.
We liked that there were a few restaurants right across the street too. If you decide on the Hyatt, see if you can sign up for their frequent stay program. We were able to use it and got a great room on a high floor looking into the atrium lobby. If you're driving, keep in mind that parking at the Hyatt is a bit steep, I think $10-$12 per night.
Personally, I think I would stay at PP because $79 is a GREAT price. I don't think I've heard of anything less than $120. Although I've never stayed there, I've heard the rooms are the largest of the 3 properties, and you can just walk to the parks at your convenience without waiting for a shuttle. I guess it depends if you can swing the extra cost and if you feel it would be worth it to have the convenience.