I stayed here for 3 nights, in a nice spacious room, overlooking the pool and beach. Cookies is a two storey building, and my room was on the ground floor. The views are much better from the upper floor (costs an extra 500 baht per night, I think). The location is excellent, right on the beach, and only a short drive from the ferry. The staff were friendly and helpful, and I enjoyed my stay there. Breakfast was ok, and there are several dining options in the White Sand Beach area.
I bought a package trip...picked up at my hotel in Pattaya and delivered to Cookies in Koh Chang (return), plus 3 nights B&B, for 6250 baht...good value considering that my room usually costs 2000 baht per night. However, the mini bus made a number of stops to refuel, and detours to pick up/drop off other passengers, and as a result, the trip to Cookies took 6 hours, and the return trip took 8 hours!!! A better option, if you are traveling in a party of 4 or more, would be to hire a taxi or minibus (3000 baht for taxi) and book the hotel through a local travel agent.
Koh Chang is a lovely island, much less developed than Phuket or Koh Samui, and all the more charming for that. It is Thailand's second largest island, but quite easy to get around. I hired a motorcycle (35 years since I rode a motorcycle) and that was great fun (300 baht per day). I was asked to leave my passport, as a security deposit, but refused. Instead, the company accepted a copy plus 4000 baht refundable deposit. I suggest that you always carry ID, in case you are stopped by police (I always carry copy passport).