Fez also drops you off and picks you up at the hostels which is a huge convenience. I know you will say, "Yeah, whatever Matt", but taking Fez is the first time I have felt like I was really "on vacation". You don't realize how much work it is to book all your transportation, navigate, and look for accommodation until someone does it for you. I didn't know what to do with myself it was so easy. The other cool reason to take Fez is you meet a lot of people. Taking public buses around it is mostly locals and Fez is 100% travelers, so you have an instant group of people (this can be bad or good).
Fez was mostly young but did have a pretty good mix of people. I did meet some older travelers and some older couples traveling as well. Note: I still consider myself a "younger traveler" despite being 30. I looked at taking Contiki but have heard it is more of a partying crowd and more restricted in where you go and what you do.
Another advantage of Fez was that I did save time. I literally saved hours that I would have been spending waiting for buses and trains or looking for hotels with the pick up drop off service. Instead of taking 2.5 weeks as planned to travel around Turkey, it only took 11 days. This gave me an option of traveling to Prague or Egypt before going to Japan, but I decided to take it easy and just chill in Istanbul before my flight to Tokyo on the 16th. I was exhausted after this trip.
The total cost of the Fez bus tour was 180 dollars which was cheap. However, Turkey is extremely cheap, so if you want to book your own buses around, you would probably pay less than half of that. What you are paying for with Fez is convenience and it is good in facilitating meeting people. God, I just read this and I sound like a f***ing Fez commercial.
Just so there is some balance, there are definitely downsides to Fez. Fez takes crappy little buses compared to the huge coaches that the big bus companies take if you book on your own. Fez also doesn't accept accountability for anything, and if there is a bad tour or bad bus ride (I'll tell you later), they don't take any responsibility for it and feel they are just a middleman. This can be frustrating.
All in all the Bus about was fantastic because I met some great people and had some great adventures. That said..