After staying at the Buena Vista Suites, we decided we can no longer go to Disney without getting a condo. To me, they really weren't suites. They just happened to have a fridge and sofa. The rooms were really small and cramped. There was barely enough room to sit our luggage around the sides of the room. Getting ready in the mornings and at night was tough. But, the rooms were clean, the location was great and we got a great deal (First night $89, second night $49). We never used the buses and we only at the free breakfast twice. It just wasn't good. I've heard other people say they thought it was wonderful so maybe they were off the two times we tried it.
The doubletree is definitely a suite. The rooms are much bigger. The beds are full size vs. queen at the BVS. We liked the Doubletree overall but my dh was very unhappy when they started charging a fee to park your car at the hotel. Also, he wanted a bigger bed because he is over 6 feet tall. I will say the Doubletree beds are some of the best hotel beds. They also give you free cookies at night. You just have to request them at the front desk. They are really good! If I had to pick between the two I would go with Doubletree because of the space and cookies

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If you have any other questions just let me know. We booked a condo for our next trip. We've never done the condo thing so I'll be curious to see what we think.