Hi,

I have the option of using either

1) A "general brand" step-up ring 37mm->58mm
and some multicoated 58mm high quality filters + rubber hood

or

2) A smaller "B+W" step-up ring 37mm->52mm
and some multicoated 52mm high quality filters + rubber hood

The larger diameter 58mm filters would fit better in the front
of the camera (that is 60mm in diameter with 37mm threads)
and would be easier to use (turning the polarizer...). This
larger size would also minimize the possibility of vignetting
if I ever need to stack two-three filters + hood. Rubber hoods
are not low-profile usually...

What makes me doubt is the quality of the "general brand" step-up ring.

Should I get the "general brand" step-up ring from B&H or not? Will it affect the optical quality of the system? (missalignments, visible degradation)?

What is the difference in cost? The B+W definetly has the edge in the brand recognition department. I'd expect the B+W to be brass and well made.

I have a general brand step-up ring that works fine (but I did make sure it's at least a metal one). I also have a B&W polarizer with a flaw in the front thread which I did not notice when I first received it. Go figure.

I think I would go with the larger ring set that allows you to use the 58mm filters. If you got another camera in the future, there's a better chance the 58mm filters might still be useable. A perfectly good stepdown ring is only 5-10 bucks.