I have the same version, I had to try out a couple different (rather cheap) LTM-to-M adapters before I found one which focused perfectly at infinity and didn't (at least appear to) go slightly past it. As you might expect, the one which cost sub-$10 was the bad one.
It's a great lens: sharp but smooth, medium contrast, good for color and B&W. I bought a couple 39mm filters for B&W and they work well with the hood since they just screw in and the hood screws on top of them. I really can't find anything to complain about with this lens, maybe some distortion to straight lines right on the edges of the frame?