Your tips Be very aware when paying money (switching 50 lira notes for 5 lira is apparently very common). Make sure you check prices on menus (insist on keeping a menu at your table for the duration of your meal). Do not be fooled by businesses who will allow you to pay in other currencies ; their exchange rates are horrible. If you want to see the most common sites be there as early in the day as possible.
We experienced both good and bad. Some of the service and product we recieved was of a good quality and reasonably priced.
However we had some bad experiences of being cheated by restaurants (no prices for drinks on their menu meant that we paid more for a glass of wine and a raki that we did for our main courses), a taxi driver who switched a 50 lira note that I handed him as stepping out of the taxi for a 5 lira and then getting aggresive and threatening when I refused to give him more money. Also one of the receptionists at the hotel took money for a bottle of water from the mini bar without giving us a reciept making me think he pocketed the money.
The old part of the city (Sultanahmed) was pretty enough but massively crowded during the day. Topkapi palace needs a full day to see, not because it's so big but because some of the displays need a wait of almost an hour to see. The green areas next to the coastal road are pretty and nice to walk along. And once you move away from the touristic areas, prices come down significantly.