But otherwise there are many very good Dönerbuden where you get fresh baked bread, very good meat and many different salads and vegetables as supplement. In this booths a Döner normally costs about 3 to 4€.
The main problem of a good Döner are the proportion of its ingredients. The salad and the meat should split roughly 50:50 and there should be not too much sauce be poured over the salad. Many makers are drowning the Döner in the sauce. And many booths put to much meat into the Döner, so you only get the meat-aroma instead of the combination of everything.
Döner is junk food, it's no better than the food you get at McDonald's or at the local Imbiss.
Funny thing. Germans discussing about Döner-Kebab in an english forum ;-)