Raid,
I'll throw out a few comments on the M5.
For 50 mm FL the frame lines on the M5 are more accurate than the M6.
The M6 has the triangles in the VF for metering and a metering area which is a circle about 2/3 the size of the short leg for the frame line of the lens used. The M5 is a much smaller spot type meter that has the measuring area defined in the VF. The meters on the M5 are very accurate and reliable. (Just have Sherry calibrate it and set it for the 1.35 or 1.5 voltage depending on the battery that you will use.) The M5 has match needle metering in the VF which is intuitive because both the aperature and shutter speeds get turned in the direction that the needle needs to move. The M5 also displays the selected shutter speed in the VF while the M6 does not.
VF brightness is about equal, but the M5 is less prone to flare.
Shutter speed is variable on the M5 but not on the M6. You can leave the M5 shutter speed dial between speed detents and it uses the fractional speed.
The M5 still has the timer while the M6 does not.
The M5 is larger than the M6, so this is a personal preference. The size of the M5 is just fine for me.
Iso is set in a window on the top plate of the M5 and a dial on the rear of the M6. Again this is just a personal preference. I like the top plate of the M5.
The shutter speed dial on the M5 is more ergonomic in size and directly under the shutter button, vs. the smaller seperately positioned one on the M6.
The M5 only has frame lines for 35, 50, 90. This is less cluttered, but can also be a disadvantage if you shoot 28, 75, or 135.
Relative to CLA and work on an M5, Sherry Krauter can take care of everything and make it like new or add a third lug to the 2 lug cameras. She truly knows the M5 inside and out. It happens to be here favorite Leica. If you get here talking about them, plan to spend a lot of time on the phone.
As a final expression of my opinion, I had the M5 and MP (basically a new M6). I sold one of them to end up with only one film camera and have ordered the M8. THE M5 IS THE CAMERA THAT STAYED. (You can also ask Wayne "Venchka" about the M5 and how nice they are after a CLA by Sherry. - He bought my back-up M5 body several months ago.)
As always, just my opinion. Good luck on which ever way you go.
Best,
Ray