Here are some images with 50/1.4asph, noctilux, cron and Elmarit:
50mm_leica_m_lenses Photo Gallery by TOM at pbase.com
I havent used the Noctilux much (since I havent owned it for long time) but my first impressions with the 50s:
Noctilux: I really like what I see, good contrast, even wide open, very nice bokeh, I like the overall look
50lux/asph: very good handling, images seem to have very good contrast and saturated color, maybe a little "finer" detail, maybe more subtile color rendition than the Noctilux but the Noctilux images look more powerfull to me.
I decided to keep them both and to sell the cron.