Let me explan why I am so exited about this trip. I am what you would call a Contiki veteran (done 9 contiki tours in last 6 years + 2 Haggis adventures + 3 SITA tours + 1 Cosmos). Have plenty of experience in the traveling industry and there is a reason why I keep coming back to Contiki (have another trip with them next month). And this tour surpassed all the expectations I had.
Before I start talking about this tour, it is imperative that you know that every Contiki tour has its own personality and the group you travel with can make a huge difference. Now, I won't discuss in detail the places you'll go on this tour because you can find that online, I'm going to focus on the awesome experience and the great things this tour has to offer.
Turkey: if you are planning on doing this tour, pray that your tour guide is Ahmet. Turkish guy with a lot of knowledge, great attitude and contagious enthusiasm. By far, one of the best tour guides I've ever had (if not the best). He is extremely funny, very respectful and honest. He was so helpful that I'll be forever grateful. Many people agree that he was one of the highlights of the trip.
About Istanbul, unfortunately the tour doesn't spent enough time there, so if you can arrive a day or two early, I highly recommend it. The tour doesn't include the Hagia Sophia nor the Basilica Cistern, although on your time off, Ahmet will offer to get you inside and skip the lines - using his tour guide license he will buy the ticket for you and get you in as a group. Nightlife in Turkey is way better than expected, and Ahmet will guide you safely to the best spots - and bargain the price of the drinks! There is so much to see and do in Turkey that you'll love it. The Ephesus, Pamukkale and Troy optionals that Contiki offer are not really optionals. You either go inside and see it or you stay in a parking lot in the middle of nowhere. So add those to the budget (is not very expensive at all).
Greece: This part of the tour is very layback, and easy pace. Greek Islands are gorgeous. Although some of the Tours / Optionals are very early in the AM still is easy to deal with. The Optionals offered by Contiki are from the Cruise Company, so you'll be walking around with people from age 1 to 99. On the Island of Mykonos, since the vast majority of the group did the optional we were together in a bus for ourselves. Pretty sure you can find the same tours cheaper. The price is unreal. On this part of the Tour, the group splits and it's harder to stay all together.
From all the Contiki tours I've done, this is my favorite one. Highly recommended. Go, live, enjoy and see the world!