Isik's place is very good especially if you intend to explore the Taksim area of Istanbul. However, if you only want to restrict yourself to Sultanahmet, note that you will need to take two trams per one way trip, hence adding the cost to your travel.
We may stay here again as our experience was good - Isik's has a flexible check in and check out plan and can hold luggage if one has a late night flight out of Istanbul. The best thing is the possibility to borrow istanbulcard - very helpful and cost saving.