After reading the glowing reviews on this site, I got in touch with Arzu to book two days of guiding for a group (we were six people between the ages of mid-20s to mid-60s). She wasn't able to take us but she offered her colleague Asli. I was hesitant at first since all the reviews I read praised Arzu but I took a chance and I am so glad I did!
Asli was fantastic. We spent two days in her company seeing all the usual tourist sites (Topkapi, Aya Sofya, Blue Mosque, Suleyman's Mosque - don't miss this one, by the way! - The Cistern, Spice Market, Grand Bazaar etc. etc.). She also took us across the water to the market in Kadikoy (not very touristy area of town where the locals live and shop) and I loved it so much that I went back at the end of my trip and spent an evening wandering around among the locals.
Asli knows what she is talking about. She was able to answer any question we had and patiently gave us a run down of Turkish history (in fact she had to repeat this history lesson again and again because some of us had a hard time getting all the complex comings and goings straight - Turkish history is not straight forward!). She shielded us from the tourist hordes by taking us down quiet back streets, getting us into fast track lines, using her guiding pass to skip ticket buying lines (this is really such a valuable part of having a guide....we visited in late April and already the lines were insane and in some cases, people were standing in the wrong lines). With Asli to guide us, we made the most of our two short days and saw a lot. She also knew some very good spots to eat.
The price per day was $350 USD (we were also given the option of paying in euro or lira). This was the price for the whole group, not per person. Our days were meant to be 9:30 to 4:30 but on the first day, we went way overtime and Asli did not seem to notice or mind. And on the second day, we started half an hour early. So I really appreciated the flexibility.
350 USD is not a small amount of money but I would argue that it was worth every penny. Here's why:
1. Our group ranged in age and we all equally enjoyed Asli's guiding and what we saw and did.
2. The tour was entirely bespoke. We customized it before and during, on the fly.
3. On our own, we would never have been able to pack so many sights into two days. The lines alone would have made it impossible (and remember this was in April, not high, high season). There's a good chance, given our group, that we would have gotten lost, become annoyed with each other etc. etc. Instead, with Asli to lead us, we were able to relax, look around, soak up the city and enjoy ourselves.
4. After two days with Asli, my husband and I were prepared to tackle the city on our own and we spent four days wandering around on our own at the end of the trip. We'd already done all the things that benefit most from a guide and we had a good mental map of the city.
5. Sometimes you get what you pay for and as I said, Asli was incredibly knowledgeable and was also willing and happy to answer our questions about more local matters (the political situation in Turkey, for example, something that is interesting at the moment, to say the least). She was candid in a way that guidebooks never ever are. There are many, many completely useless guides around and I think this was money well spent.
A note about Arzu: I communicated with us before the trip and she was also prompt and helpful in her relies, giving me recommendations for things outside of Isanbul as well.