Location, Location, Amenities
Biggest advantage for Bonnet Creek is proximity to Disney Parks -- closer than some Disney hotels, and much closer than Downtown Disney hotels. This can make a huge difference on super-crowded days. It is also nice to be able to return to your room on a day you intend to visit multiple parks. Last trip, in November, we used the shuttle for two days, drove/parked three days, and visited non-Disney parks for two days. The shuttle can get you closer than parking, so even if you need to wait for the shuttle, total time can be a wash. Also, depending on your party, taxis are an option. To save $$, use Disney transportation to get you close -- e.g., transfer to a nearby hotel. If you plan to park for 7 days, strongly consider getting at least one annual pass -- parking is thrown in, and you have access to other discounts (including a dining discount program).
Second advantage is ready access to other parks -- because of the proximity to I-4, you can drive to SeaWorld, Aquatica, Universal Studios etc. as fast as some Kissimmee properties.
Finally, because the property is newer, the amenities are a bit higher end than other properties. If the hotels are completed 2009-10 (Waldorf-Astoria, Hilton, Wyndham) amenities will get a big bump up -- e.g., walking access to sit-down restaurants, spa, etc.
Notice I did not list room quality in the top three. In November we stayed in an older tower which was beginning to show its age...