I've stayed at All Star Sports, Caribbean Beach Resort, and off-site at a Days Inn (maingate) and Orange Lake Resorts.
You can save a lot of money by staying at places like Days Inn, but they are not necessarily as nice as far as rooms and pools and may not have transportation, or run it frustratingly infrequently. With the discounts they sometimes offer to the UK, I wouldn't stay at one of these again (my US-based parents booked it and they drove us in to the parks...which also meant paying to park).
Orange Lake is my Dad's favourite, so when traveling with him, we stay there. We've stayed their twice. The pools are nice, the place is clean, and because they are all timeshares that you are renting as a hotel, they all have separate bedrooms, living rooms, dining area, and a big full kitchen with cooking supplies. There is a lot of square footage. You have to drive though (and then pay to park). The parks are not far to drive - the property backs onto Animal Kingdom - but there is always a drive at the start and end of the day and anytime you want to go back to the resort for lunch, a break at the pool, etc. They offer a shuttle, but the added price for it is not something we were comfortable with and the schedule seemed restrictive.
Onsite, we love. When booking for just my family, without grandparents, this is my preference. There have been some comments that the rooms in the All Stars resorts are small. Yes, they are smaller than some American hotel rooms, but they are bigger than many places I have stayed in in the UK. To be honest, I didn't spend a load of time at the All Stars - I was there with a toddler and was basically there to sleep when not at the parks. The bus transportation was really convenient and saved parking charges. I can't recall having any issues with the food court on the days we ate there rather than at the parks.
Our best experience thus far as been the Caribbean Beach Resort. When planning, I had originally assumed we would be staying at an All Stars or Pop, but there was a message on-line that I could get a free dining plan if I booked a Moderate instead of a Value. I looked at the price difference and thought about the cost of meals and decided it was probably less money and nice to have the convenience of a dining plan. This also meant we had pre-paid for food in GBP, so didn't have to convert to USD. The resort was excellent, with a better pool than All Stars, and activities at the resort's main building (they might do this at the All Stars too, but we missed them). One day we came back for a lunch break and my daughter did a limbo party. Another day she was asked to dress the Duffy Bear for the shop. One evening we got pizza at the main building and watched Tangled on a big screen by the lake. It was an awesome resort. And, there was bus transportation that left from just near our room or from near where we had breakfast (the buses circle around Caribbean Beach Resort, so you don't have to walk far to get one). The early morning views were excellent.
Top tips - see what you can find for deals, think about cost of transportation or parking, and don't be put off about the size of rooms in the US - everything is bigger there.
