We recently visited Istanbul and our guide Kamal was very,very good and the driver was excellant - always on time and very skillful at negotiating the heavy traffic and roads around the city. The only drawback to using this guide service is it's cash only policy, which for a large family group can be an inconvienence and their other guides are good but no where near the caliber of Soner

Made 8hrs Istanbul tour with another couple.
Kemal our tour guide was extremely good and did a wonderful job explaining the histories behind each scenic site around

Mr Eyup our driver was awesome! We booked him the next day (as our ship docked at Istanbul for 1.5 days) as our driver to visit a local mall. Not only that he was a safe & punctual driver - he actually took the time to explain to us the places we've driven by as well.