the M is a smaller, but its weight is surprising (the top and bottom plates are brass)
the body will weigh about the same as your 6D, but the lenses will be much smaller and lighter.
have you used a rangefinder before ? the M is manual focus only, you can either use the mechanical coincident rangefinder, or focus peaking on the back screen/optional EVF (only on M240/M-P)
The M240 is my favourite camera ever, i absolutely love mine and take it everywhere with me, but i wouldn't recommend it, its very expensive and a bit limited.
lens choice is from 16mm to 135mm, although many say that 90mm is about the limit of accurate focusing
there is no zooms (ok, there is the WATE and MATE tri-elmars, which have click stops at three different focal lengths, 16,18,21 or 28,35,50mm)
you made a few points in your post my responses are in blue
I mainly shoot
-Astro (hardly ever really but would like to)
-Family snap shots
I use mine at work and for landscapes and family pics
-bring my camera anywhere its small and easy to carry
-lighten the load so easier to carry the body will weigh around the same, the lenses ail be smaller and lighter
-not be embarrassed to pull out in tight crowds (this happens with travel, hard to pull out that camera with a 70-200 on it and not get stares)this is a mental thing, you get used to the stares, people do tend to ignore the M though
-Enjoy photography (sometimes my 6D feels more like work then play) I enjoy photography but lately have been leaving my camera at home because its a lot to carry around.this is the reason i bought mine, i want a camera that is fun to shoot, and separate from work, something small i can take everywhere (and i love the proper rangefinder)
I just wanted to see if anyone else has made the move from FF with lenses to the Leica M system and looking for your input. I figured this would be the pace to ask.
I didn't switch, i have a pair of 1DX at work, and the M is my personal camera, they complement each other nicely (1DX, big, loud, good lens choice) (M, Tiny, Quiet, feels good to use, people tend to ignore you with it and forget they are being photographed)
there is a "Leica Lovers Anonymous" thread over in general photography sub forum, might pay to ask the guys there, or at least alert them to this thread (I see you already posted on LUF)
I have an M240 and 50mm f2.5 Summarit