I have been to Defne several times (I live 2 houses away from it!) and I think it is a solid choice- great service, hospitable, family run, fresh, traditional with more innovative daily specials . The outdoor seating in the garden is great, with a view over the canal. In October, maybe not. I was there two days ago and had a special- medallions of veal in a pine nut and cream sauce with rice, and a salad along side. Really nice. Lentil soup is traditional as an appetizer, they do it well here. Typical lamb on a stick dishes are available here as well- the one with the eggplant is my favorite. Big chunky "greek" salads. Sigara boregi. The little filled pastas with meat or spinach with both yogurt and tomato sauces. Fresh fish on Fridays and Saturdays. Planufer 92c / 10967 Berlin (Kreuzberg).
There is also an new grill restaurant not far from Defne. Corner of Schönleinstrasse and Bökhstrasse, (in Kreuzberg, naturally) I think. Have not tried it but it looks nicely decorated, with a wood-fired charcoal grill for sis kebab, kofte, etc. It's been mentioned in the weekly mags and I see Turks and Germans eating there. Worth a try. Can get back to you on that one.
Just this week I wrote about a Turkish restaurant in Berlin called Yesil Firin, check my review bellow.
However, it is not in a very touristy area. Hasir is in all the touristy places: near the KaDeWE, near Hackescher Markt.
I haven't been to Dafne, but it is considered to be good.