Docter Klassik series is a very good option. Docter is an east block Zeiss, actually it is a real original Zeiss from Jena Germany. I use 6x42. My favorite. I have S&B Klassik 6x42 and Leupold FX III 6x42also. All three are very close, but I found using Docter more often. Again all three are close and here is my ranking by quality and durability:
1. S&B (10 out of 10). Dual windage and elevation indication. You know your setting all time
2. Docter (9 out of 10). Very simple and robots. 9 because no dual indication ( maybe it is a plus actually)
3. Leupold (8 out of 10). I bit less light transmission in twilight (one man personal opinion)