Please note: Leica glow is something that you can get from most older uncoated lenses. I have Russian optics that are very, very good lenses. I have a Canon lens that gives me incredible results. It really doesn't matter *who* makes the glass as long as its made well and, in the case of the Russian glass, adjusted well.
Disclaimer: These are my opinions. I like Leica glass and look forward to owning some, so please don't take my words as Leica bashing or the like. Thanks.