Four Seasons or Ciragan Istanbul?
 

We can not make up our mind on what hotel to choose. Please help!

Both are ezcellent hotels. Four Seasons is in Sultanahmet within walking distance of Aya Sophia, Blue Mosque and Hippodrome area, and a short tram ride to the Grand Bazaar and Topkapi. Ciragan is situated in a beautiful setting on the Bosporus a good distance from the tourist sites. If your primary interest is tourism and enjoying the magic of Istanbul then I would opt for the 4 Seasons. Enjoy Istanbul!

Hi. Ive stayed at both hotels. Both are very good though i prefer the four seasons because its smaller, cosier and the service is very good. Istanbuls amazing! have a good trip.

Just in order to complete the info you already received by CharlieB and abcd_xyz, the Kempinski has a lovely outdoor pool right by the Bosphorus and an indoor pool, too. The FS does not have a pool.
I would prefer the Kempinski. Whereas the FS is right in the middle of Old Town close to sites such as Topkapi Palace, the Blue Mosque and Aya Sofia, the Kempinksi's location does not strike me as that bad. It is a cab ride from Old Town, true, but therefore it also spares itself the hustle, bustle and continuous haggling prevalent throughout Old Town.
Istanbul is also more than just Old Town. It is also Dolmabahce Palace (which is much closer to the Kempinski) and the vibrant area around Taksim Square. That, too, is to be reached easier from the Kempinski.
After all, it's a matter of personal taste, though.
Enjoy your stay
hsv

This is a minor point, but in my opinion if anyone has time in a few stays' stay in Istanbul to lounge around a pool, that's too bad -- there is much too much to see in Istanbul to spend time doing that. On the other hand if it is important to take a half hour swim daily as part of your routine, or something like that, then I'd understand the desire for a pool.

Thank you to all for the valueable feed back.