Keith, yes I also have 3 really useful and characterful C-mount lenses for M4/3. My shooting buddy who gave them to me says they don't have the coverage for his APS-C NEX.
Pavel, I have a collection of Voigtlander in LTM, plus the Nokton 50/1.1 (M) and some Canon LTM and even an Industar. I love them all, though I mostly shoot on film.
Tim, I recently got a Zeiss Ikon ZM, which is great with the Nokton, though I miss the Hexar's motor drive. Up till now I've only had the one M-mount lens for reasons of flexibility, but sometimes swapping adapters is a pain. Which Zeiss lenses perform the best compared to Voightlander?
Collection: GR1 GR1S GR1V(date) GR10 GR21 R1 R1S R1S(gold) R1E R10 RX60 GRD I-IV GRD Ltd GX100 GX200 GXR A12-M G4-Wide 500ME