Me, my girlfriend and our two friends stayed one week at Ersah otel. The staff and owners were very nice and helpful (although they didn't speak english very well), but that wasn't a problem. Anything you asked them the answer was always no problem, was it considering the music at the pool, the food, the breakfast timing, anything.
The room was clean and good size, but the bathroom was small, and there weren't warm water in the shower. It went from ice cold to red hot. The nightlife in the nearby hotels were kind of noisy and if you lived on the bottom floor of the hotel, you could hear the music from the pool very loudly. It's roughly a 10 min walk from the beach and you can get to the centrum in 10 minutes with a minibus. The breakfast was mainly bread with sausage and cheese and vegetables and tea, but they would make you an omelette by reguest. Overall a good experience and had a great time in Kusadasi!