I stayed at Santa Fe with my son for a full week in September (2011) and really rated it. The cost difference between Santa Fe and other on site hotels was significant when staying for 7 nights, so it was an economic decision, but one we didn't regret.
Refurbished room near the river and pathway to parks, making it an easy and pleasant walk. Our room was smart and my son really liked the theming (we have more photos of the 'cars' beds than the castle.) In particular the shower was amazing, the beds and pillows extremely comfortable, big (for me!) flat screen TV, and the housekeeping service was excellent. The corridoors are worn but it really didn't matter as we only passed through momentarily, and it sometimes took a few attempts to get the door card to work, which again didn't bother us because we always got in.
We took kettle, mugs, tea towel, tea spoon, and picnic cutlery and plates, none of which are provided. Shopped around for everything from tea bags to roast chicken and bread, and had a couple of delicious cheap meals in our room at times when we just wanted to chill out and recover for a couple of hours. Our housekeeper kindly cleaned around our 'kitchen' area every day.
Unexpected bonuses were the acres of storage space - two of us with generous amounts of baggage didn't touch the sides of what's available, the very nice coffee at breakfast (best I found on the holiday, so I made the most of it!), and the in-room safe, which really made a difference to my feeling that our important things were secure. My son took gadgets that we would have been gutted to lose, and staying a week meant we had large amounts of cash and various cards with us. The safe really put my mind at rest.
Personal bonuses were the lack of fragrances in the hotel (my son suffers migraines triggered by chemical perfume smells) and the quietness - no piped music anywhere near the rooms.
The amenity block - restaurant, shop etc - wasn't as impressive as the five star hotels, but we didn't use it much anyway. With so much choice on site you really don't have to, although we did take advantage of the bar to end some of our long days with a few cocktails - much cheaper than other hotels even though exactly the same.
If you're looking to make the most of your budget I think Santa Fe is ideal, particularly with the garage shop so handy for odds and ends at up to one third of park prices. We had decided to book the cheapest hotel so that we had more to spend on doing things during the daytime - shows, trips, meals etc - and for us it worked perfectly. I'd definitely stay here again.
Hope that's useful!