As a long time Leica M shooter but also someone infected heavily by GAS I own and use several systems.
Every couple of months a new camera comes, other go, some stay long (like my 5dIII) others are sold even after a couple of months (some of the mirrorless).
Today we often here questions, why people use "overpriced" Leica M equipment.
For me the M is still a very very good compromise between:
-excellent IQ; specially not just a good camera but also many excellent lenses
-very nice user interface
-relativly fast to use for a manual focus camera
-Yes, my Canon 5dIII is faster, has better high ISO, but it is indeed much bigger and the images do not have the same pop as those from the Leica M. (maybe PS specialists can make them pop)
-M43 is also small, nice and fast, but the IQ looks flatter and I dont like EVF
-The Pentax K (my 2nd favorite system at the moment) also has a very nice user interface, is kind of small, fast, good IQ (even though colors seem overcooked sometimes) and has good lenses, but the M lenses are even better and the M images look more neutral and natural to me
-the Leica S beats them all in IQ but is big and expensive
-So yes, I still think the M-system is an excellent photographic tool and not just a luxury for snobs. It is expensive, however it is also very stable in value, specially the lenses. I love the lenses, the viewfinder (specially for people who like 35 and 50mm FOV), to be able to see around the frame in the viewfinder, the colors and the intuitive handling; I feel I dont have to concentrate on the camera but can concentrate on the subject.
For certain things I prefer a fast AF camera or a larger sensor, but if it was just one camera system it would be the M for me (or the Pentax K )
Dont know why I wrote all this here...