I was just at the Hyatt Regency Istanbul and loved the property. It definitely feels more like a resort than most Regency properties.

Definitely worth a visit to the spa -- even if you aren't going to get a treatment you can use the sauna and steam rooms.

There is a lot of construction around the property right now which will be good for opportunities to walk to other restaurants/shops/etc, right now you are kind of stuck on the property unless you take a taxi.

Here is my more full review if you are interested:

http://singleflyer.com/2015/09/02/hy...-hotel-review/