Most of the Istanbul airport hotels are in Arnavutkoy. It's a gritty town, full of dirty construction and noisy traffic. I had a 23-hour layover that I didn't want to spend in the airport but was too tired to see the city, which I knew from having lived in Turkey before. My plane arrived early and I was going to leave early the next morning, so all I wanted to do was to eat breakfast, take a shower, and have a nap in a comfortable room. There was no early check-in. So, I paid extra for check-in. The manager could see I was cranky and tired, so he gave me an "upgrade" to a small room he called the executive suite. (The manager did the best he could; hotel policy was the problem.) As for food, even though I arrived before 10, when breakfast should still be served, it was unavailable, so I had to go out to find something myself. Then I showered and slept. A shuttle was offered, but it was considerably more than a taxi. I rated the hotel "average" because it was clean and the shower was nice.
All hotels calling themselves "airport" hotels should offer anytime check-in. Expedia has the market clout to make this standard practice. For properties calling themselves "airport hotels", if early check-in is not free, it should be boldly stated upfront. I would not choose to stay there again, and I would recommend against anyone staying in Arnavutkoy unless it's an emergency.