Host is always ready in case you need him. He sent someone at the airport to transport us. Good communications. Came after midnight when another key when needed. Location is as advertised; within walking distances of major sites: Hagia Sofia, Palace of the Sultans, Blue Mosque, Istanbul University, cruise ships on Bosphorus, Bazaars.
As visitors for the US, we could afford good cooked meals without looking at the prices.
Don't believe the news about Turkey being unsafe. We walked in poor dark neighborhoods late at night without fear. You might see a soldier or policeman at the entrance of famous sites, before you go through a security gate.