We've stayed at Amari Coral Beach, Kata Beach Resort, and Chedi over the past few years and I'd say that the Kata Beach Resort was the best value along with a fine beach with retail and restaurants just outside the hotel. Not a five star hotel by any means but clean with good food and nice grounds. In fact, the rooms are bigger than the ones next door at Boathouse. Easy to go to the excellent dining that they have at Boathouse, though.
I'd like to try the Kata Thani sometime as well.