Location wise is the best, you can find anything you need in the area and Istiklal St. and the Metro is just a walking distance. Taksim is no doubt a busy area but the house is situated off the main roads, so you can still have some peace and quiet at night.
Berk is also a great host. He helped us book the airport transfers and even go above and beyond and taking his time off to help us during an emergency. I can't thank him enough.
Thanks to Berk and his father, we had a great 1 week stay in Istanbul :)