[Leica] Help with a Nikon F/F2 to Leica M transition

["The Beal's" <jbeal@bendnet.com>]

Dear LUG'gers,
   I've been lurking in this mail for a couple of years, absorbing all
words of wisdom I can to make a successful transition to the world of
Leica.  The latest Nikon F/F2 posting seemed relevant enough for me to
make a posting.
   I have used a Nikon F Photomic (flag meter) for 21 years.  I'm an
amateur photographer drawn to candid, available light, star trail, and
occasional landscape and black & white photography.  Candids are out
because of the loud mirror slap, and dim viewfinders and minimum
handheld speeds of 1/60 make available light difficult.  The above
reasons and Leitz glass tell me I might be happier and more productive
with a Leica M.  With your kind assistance (particularly from
former/current Nikon F users), I have a few questions for the group.
   In looking for an M body, I'm torn between metering convenience and
focusing practicalities.  The M6 is attractive because of the TTL
metering, which is familiar to me via Nikon, and the prices have really
come down.  It is also newer with a potentially longer service life. 
However, being burdened with eyeglasses, the M3 appeals to be because of
greater focusing accuracy and I have yet to hear much negative about the
M3 in this group.  My only hang-up about an M3 seems to be the process
of metering: is it that much more involved than a TTL system?  Is
metering an M3 with black & white filters more of a chore than with the
M6?  What does an M body undergo in a CLA, and how much sway should it
have over a similar M without it?
   I intend to use a Summilux-M 35mm/1.4 (not flush enough for an ASPH)
and eventually acquire a Summicron 90mm/2.0.  Are there any particular
traits or Achilles heels with these lenses (fungus, element separation,
etc.) for which I should be on the look out?
   Any help on any of these questions is much appreciated.  

Thanks and Happy Holidays to all.
John Beal II
jbeal@bendnet.com