Anyone have any personal experience or insight from friends about the Four Seasons Bosphoros?

We plan to spend a few days in Istanbul after our cruise next year (first time in Istanbul!!), and we know we want to stay on the Bosphoros, but we are trying to decide between the Four Seasons and Çırağan Palace. I have read about Çırağan Palace on some other posts, but have concerns over some of the recent reviews I have seen on other websites. Just wondering if anyone had stayed at the Four Seasons and could compare.