Difficult to change the lens or film limited choice/availability of lenses unless you like the 50s lenses or the few modern Cosina lenses.
A Canon VI, P or 7 is a real system rangefinder way faster handling.
And the Canon lenses from 50s wiped the floor with Leitz ones.
All hype.
I respect your opinion, but I don't agree.
First, the S3 is much easier to load than the m2/m3. SignificNtly easier.
Second, the lens mount is easy enough once you know what you're doing. Neophytes ten to have trouble because they don't realize you have to set the mount to infinity b4 lining up the lens.
As for lenses, the s3 has a finder that accomodates the 35/50/105. It allows you to use the W- Nikkor 3.5 1.8 in S mount, which you can pick up for 500-600$. Its the eaxct same optical formula as the LTM version which routinely fetches up to $2000, and is in all respects as good as the 35 Summicron. As for 50's the Millenium 50 1.4 is a remarkably good lens, easily the equal of the summilux. As for teles, the 85 and 105 are both superb. Plus, if you like modern optics, there's a full line of VC lens, same otical formulas as the Leica versions, easily enough found on ebay.
I love my Leicas - an IIIg, an M2-r, an M4, M5 and M8. But in my mind the Nikon rangefinders are their equal, just different, and they are much less expensive both for bodies and optics.