Auto Close-Up Lens for Mamiya 6

I can barely find any (bar Ken Rockwell's) opinion on Auto Close-Up Lens attachment for Mamiya 6 + Mamiya G 75/3.5. Does anybody use it? Is it worth considering - not necessarily for true macro (a range-finder simply doesn't suit), rather for portraits, when I don't have any other camera at hand. For sure i deteriorates quality, but the question is how much.

I had one fore a while. It was amazingly sharp! I saw no image deterioration at all. The problem is in the framing. Parralax becomes a huge problem when viewing that close. If you done mind a "crap shoot" for framing it does a good job. Definitely not macro though. I think it would work good for closer up portraits than are possible on the lenses without the close up attachment.