The two bathrooms that the kids suite has would be nice. But other than that, I would highly recommend staying onsite. Always and forever! The Hojo is a great property and when the onsite rates are sky high, it can be hard to justify paying those rates. But I have stayed at both Hojo and PPH (and the DLH, GCH and several other offsite places) and staying onsite is very nice and always a winner for me. The PPH is much more of a hotel than Hojo is. And the Disney customer service you get when you stay onsite is hard to beat, but of course the Hojo has very nice employees as well. But nobody does customer service quite like Disney based on my many experiences (over 25 onsite stays between DL and WDW).
The perks of being onsite are as Molly listed, but I just want to stress how much of a perk having Magic Mornings, each and every day they are offered is. And that pool slide is beyond cool at PPH. I also don't care for the way the Hojo splash zone doens't have a regular pool right next to it. Splash zones are great, but with the only true pool being completely separate, for me that would bother me. However, if you have young kids, toddlers in particular, that area would be a winner. For kids the age of mine, the quiet pool would be way better and the lack of slide at that quiet pool would be not so great! So for sure the pool issue will be different for each family depending on the age and likes of their kids.
Oh and the PPH pool deck is a great place to watch the fireworks.
The PPH rooms are very nice, you have two queens, a day bed (that is very comfy) and they are spacious. There is no balcony which is a bummer.
The walks are even as far as distance, but walking up DTD and or through the GCH is beyond better than walking up Harbor. You can also take the monorail back and forth which at night in particular can be very nice. The walk up a busy city street that comes with traffic noise and pan handlers is always a bit of a magic buster for me. Although that panhandling thing has been hit or miss, but I have had some not so great experiences with that walking up Harbor a few times, once in particular that really upset my daughter.
You can't make a bad choice which is good! Overall, I think the room decor, general feel and locatioin of the PPH are more upscale than the Hojo. And this is a good deal so it might be nice to jump on it while its there! But the Hojo is certainly very nice and I am not at all saying not to stay there (so Hojo lovers don't flame me please!)