My family and I stayed at the Wailea Marriot, and loved it!! We originally were staying at a hotel in Lahaina, but checked out after one night since it was disgusting. We were soooo thrilled to walk into the Marriot, which was beautiful! The hotel is located in the perfect location, minutes away from the shops and restaurants of Wailea and is minutes away from the Four Seasons and Grand Wailea. It is located right on the beach, and has access to two swimmable beaches with great snorkeling. The food is excellent by the pool, and the fancy restaurant upstairs is okay (you can get better food for your money at the four seasons). The room was perfect. We booked a standard room, but got a full ocean view. The staff was great as well.
I have stayed at the Four Seasons next door, and thought that the Marriot was not much worse. Its a great hotel, for a great deal.