We spent 3 weeks in Armutulan this July and loved it.

There was enough to do in this area and no need to venture to beachfront if you didnt want to. However, we did take the dolmus from Armutulan into main beach and marina area on a couple of occasions. Whilst we enjoyed these little jaunts we all agreed that we wouldnt like to stay in the busier part of Marmaris for a few weeks. I do agree with a previous poster though -
you dont need to be around bar street etc. amidst all the noise. There are loads of nice properties in side streets that can be as quiet or a noisy as you want it to be.

Marmaris is a resort that suits all ages. I especially like the month of May there when its not too hot and you dont have the crowds.