Keeree Ele Hotel is a great place to stay on Koh Chang for a modern, comfortable and luxury-feeling hotel that is still affordable. It's sadly not by the beach (which has brought down the price) so if you don't mind that this is a great place to stay!
There's a restaurant diagonally to the left of the hotel called "Thai Food" - highly recommend it! Local prices and food amongst the other overpriced tourist restaurants.