I travelled through Turkey to the Syrian border in 1984 (just after the military coup) and returned to European Turkey in 2009.
The changes in Istanbul were remarkable - and largely for the better. The people were, on the whole, much happier, wealthier and far more Westernised in outlook. The 'cult' adoration of Attaturk remains but is, understandably, a more gentle, fond respect for the Father of the Turks now than the fascistic idolisation I saw 26 years ago.
I remember a sign in a hotel which read, "Paradise Through the Barrel of a Gun."
The food had changed for the worse, more bland as hot chilli has fallen from fashion and I only saw one old boy in traditional 'Turkish baggies' when once they were everywhere.
I was only hassled once by a carpet seller this time whereas before every step seemed to bring new calls of, "My friend! My friend! You come with me, my father, he has carpet shop!!" all over the country. If you see this about to happen to you either run up to them and say, "My friend! My friend! You come with me,
my father,
he has carpet shop!!" first and enjoy their confusion or go and do the whole 'carpet shop thing' with them - you should do this once, anyway, just for the experience, even if you don't intend to buy.
Generally, you sit around a comfortable room decorated with fine carpets, drinking chi while a regiment of staff unfurl beautiful rugs in front of you. It's always been an totally male thing in my experience, and a rather macho business procedure, oddly. As I never intended buying this last visit I took along a few cigars to offer round when leaving - I just went for the show and the tea so figured a 'thank you' was in order.
I was told by travellers who had been in Asian Turkey in '09 that it is still very much more conservative than the western provinces where young women adopt Western dress. I was surprised to befriend a beautiful, young Turkish woman, a student in Edirne, something that was unimaginable 25 years ago. If you are in a particularly touristic area it'll probably be utterly Eurofied. Worth getting out into the country sometime if you can, I think, but you may just be going there for the beer and the beach?
Something repugnant that hadn't changed, though, was the prominence of sexism amongst the Turkish men. Western women may be regarded as loose or as a trophy and blond women particularly attract a lot of unwanted attention. A friend of mine was almost raped in '84 (while her boyfriend was in the shower!) and I heard similar stories from fellow travellers on my last trip, regrettably. I don't mean to alarm you, but there is a bit of a culture clash on acceptable behaviour on this issue. Dressing modestly in more traditional areas is probably advisable for any women you are with if you're off the tourist trail.
If you haven't already, check out TripAdvisor's restaurant reviews, too.
Hope you enjoy yourself.