Muse's place is great. It is a five minute walk from the Bosphorus and the tramline. It's also a short walk to the Galata Port walkway. My wife and I like walking and we were an hours walk from the Hagia Sophia area and half an hour away from Galata tower. It's also a ten minute walk to Taksim and Istiklal. So well located.
The place is clean and well taken care of. The facilities are good. Good shower and tub.
My only two issues would be that the flat is on the fourth floor, there is no elevator. My wife and I were ok with that but if you are not fit, or older, or have a problem with stairs it will be a problem. The apartment is also located halfway up the hill to Taksim. So expect a lot of ups and downs.
The second issue was that the terrace does not have any blinds so you might have an issue with privacy.
Overall I'd recommend staying here. The host is responsive and welcoming. The place is good (if you don't have a problem with hills and stairs) and clean. Safe.