I stayed in the Opus with my husband and friend, for just one night, as we had business in Kusadasi. For us it was SPOT ON. The one bedroom apartment was ideal and sufficiently equipped for our needs. The apartment and communal areas of the hotel were very clean and the staff welcoming and polite. As it was mid November the pool and pool bar were not open, but looked extremely well looked after and would be very inviting in the warmer weather. We ate out mostly, but made breakfast in the apartment, however the menu looked very reasonable.
Although, not a beachy hotel, it was within walking distance of the main bus station, with it's many cafes and services, so perfect for getting around if you haven't a car. The reliable, cheap buses can take you almost anywhere, locally or further afield.
For us it ticked all the boxes, and I wouldn't hesitate to stay there again. Inexpensive too.