Flickr: Discussing Autocord (which one), Diacord G or Yashica Mat? in TLR.
here are some interesting and useful discussions on comparison between Minolta Autocord, Yashica Mat, and Ricoh Diacord.
I have not used an diacord before.
If you let me choose, I will most probably choose the Yashica Mat.
TLRgraphy 
I’ve had and used all of them. The original non-metered
Autocord with 1/500s shutter, a Ricoh Diacord L and a couple of
different YashicaMats. Of these three my favorite camera was the
Autocord based on the image quality alone. Still, I only use a
Rolleicord V these days.
Along this range of TLR, my preference would be Yashica D. Autocord is very good too. I tend to use mamiya tlr and Rolleiflex more often 🙂