We had two guided tours in Istanbul by the same company. The first of the bazaar was just OK; guide mainly told a couple of anecdotes and took us to some shops he knew. Nothing bad, nothing good. Our guide for the palace was outstanding. Extremely knowledgeable and entertaining. He really knew his subject matter and communicated it well.

the guide was really prepared and kind, ready to give as many explanation as needed. The only mole was that he did not have a mic so due to the crowd it was a bit difficult to hear. Quite and enjoyable a quick way to discover the palace. I'd recommend also the free audio guide

although pricey, it's a great tour. you can find yourself there for hours. guide was good and informative but skipped parts so you can go after by yourself. harem tour is extra but really good and you see many areas that were only for immediate family. Long queue for holy relics, I waited 70 minutes, people try and jump the queue which is not very fair but it's not managed by staff at all. huge place and 4 large courtyards so you can find space to sit too. Church also cost more to visit. you will be tired after all the walking and stairs to rooms. not good for people with mobility issues, although I saw a few people in wheelchairs.