We recently came back from a Thomson 7 night gulet cruise between Marmaris and Fethiye and had a wonderful relaxing trip even though it is definitely not '5' star luxury.
The gulets are rather basic with no air conditioning on board and very small ensuite cabins (our gulet the Aganda had 9 cabins) but we hardly spent anytime in the cabin.
It was very relaxing as we cruised from bay to bay round the coast. A worry was how 9 different couples would get on but although there was a wide age range (from couples in their 20's to couples in the 60's) everyone mixed together and go on well.
The captain and the other 3 crew members were very friendly and did everything thet could to make sure everyone had a great time even if they just wanted to chill out and do nothing during the voyage. The cook worked wonders preparing great food in a very small galley. It was simple food but very good quality.
Downsides - very small basic cabins which are not air conditioned - some decided to sleep on the sun deck under the stars.
The big dining table was quite crowded with 18 sitting together at meal times
Drinks - you only settle up at the end and do not get a receipt/chit when you order drinks so some people had a shock when they had a large bar bill at the end, especially as the drink prices were not prominently displayed.
If you want a great 'chill out' holiday doing very little and are willing to share with 8 couples you have never met then try this holiday. We enjoyed our trip so much that we would be quite happy to book another gulet cruise in the future.