This apartment is an excellent choice if you want to be close to Taksim square and public transport to take you anywhere in Istanbul. Personally we like to walk so we really liked the position of the apartment as you can basically do all the major sites on foot. If you prefer public transport Tram T1, which will take you to Sultanahmet, is literally only a short walk away and you can use the same train to reach boat pier in Karaköy which takes you to Asian side and Golden horn.
There is a good shop not far from the apartment where you can buy anything you might need for your stay.
Bed is a good size for 2 people and the living room sofa can easily be used for a 3rd person. Air-con is excellent (we were in Istanbul at the end of August) and WiFi works good.