My experience at Carlton Hotel was very good. The room was big, clean and the staff helpful. The breakfast is not excelent, but also it's not bad at all. The hotel is not in the downtown, however it's just 10 min away from it. The trams 5 and 9 take you to most of the main attractions in Prague. In the worst case, you'll have to take another tram to you final destination. The only negative thing I might point out would be the bed, which is not so comfortable. It was just good to me, but I imagine someone may find it not good. In short, I'd stay there again.