I'm just finishing a two-week charter out of Marmaris. We'll be returning the boat (a Jeanneau 409) tomorrow.
The sailing is fabulous here. There is plenty of wind (the "Meltemmi") and the gusts can be pretty fierce, since the topography is uniformly mountainous. There are literally dozens of beautiful bays to duck into and many have nice restaurants where the dockage is free if you patronize the restaurant. Anchoring is not a problem so long as you have lots of chain and a line to run ashore. It's deep here, and if you can find a spot with less than 10 meters of water you grab it.
There are lots of ancient ruins (Greek, Roman, Hellenistic, Ottoman) to visit. Folks are friendly,(most speak at least some English) and the food is excellent. In particular the local beer (Efes) is first rate, there are good local dry red wines and, of course, raki.
We didn't see too many other Americans or Canadians, although we did run into one couple from Newport who had their boat (a Swan) shipped to Istanbul ten years ago. They keep it in Marmaris when it's not in use. We have met lots of Brits, Germans and some obnoxious Russians who insisted on anchoring about 15 ft from us but then were forced to more when they couldn't keep their boat from swinging into other boats.
I will definitely return here, finances permitting. Even with the airfare it's no more expensive than the Carribean and way more interesting.