If the optical quality hasn't changed, it's a lens to love. (I understand the M-mount 28mm f/2 doesn't perform as well as the LTM f/1.9, though I haven't tried the M-version myself, it's just hearsay, and I tend to put very little trust, if any, in online lens reviews). What I like best about the original version is how tiny it is, considering I rarely use it. I added permanent 39mm filter threads by epoxying an empty brass filter rim (minus the male threads which I ground off) inboard of the hood fins. I'm not sure how much of a noticeable benefit rangefinder coupling would be for me, as I tend mostly to hyperfocal even my 21mm lenses that do couple (biasing the set point if the main subject falls much closer or farther from the hyperfocal distance). If and when I spy a used one I might give it a try.