Let's put it this way. You've heard about a beautiful city of unimaginable riches – only a couple of days' travel over the hills to the west. These days it's no longer an adventure in the wilderness, you can basically just buy a ticket and go. But the ticket is kind of expensive and you have heard all sorts of rumors... Some say the city isn't worth going anymore. The people have grown vain and the beer has gone stale. Some say it's a plague-ridden hellhole. Some say it's pretty much the same as everywhere else.
It's hard to tell who has it right, or indeed, whether any of the storytellers have actually been to the fabled city in recent times. So, would you rather sit around listening to the endless tales of old men – or ride to the city and, for the very least, come back with some stories of your own?
^^^^
THIS
For something with such emotional draw, there is nothing like your own experience, for better or worse.
A very large part of the Leica experience is the M body haptics and ergonomics, and other cameras simply do not have these things. The heft and curved feel of the camera in your hand, the muted click of the shutter, the velvety advance lever, you won't find another kind of camera like this.
I must admit to a perhaps irrational line of thought when it comes to film Ms and lenses. If I shoot with the M9, I am happy to use Leica, Zeiss or Voigtlander lenses, as the image it largely created by the Leica-chosen sensor and processor inside. The M9 images have a distinctive character which comes through every lens I put on it, which makes every image a 'Leica image'.
But if I shoot with the M7, the image is created by a third party - film - and I find myself wanting to use only Leica lenses to distinguish this as a 'Leica image'. But that is just me, others will feel differently. I obviously hold a fair attachment to the idea of the Leica experience and output.
On the other hand, the photographer Derek Woods has been shooting a superb 365 project using his M6 and primarily a Voigtlander 28mm f2 Ultron. Kodak Portra 400 is his film. Derek understands lighting, exposure and composition like crazy, if his work is anything to go by.
http://365daysofleica.tumblr.com/
https://www.flickr.com/photos/dtwoods/
Warning: NSFW
Lots of people will tell you that Voigtlander and Zeiss do a superb job in comparison with Leica for lenses. Zeiss lenses, particularly the 21, 25, 28, and 50 f2 Planar are so close to Leica image quality that the mucho extra cash might not be justified for those on a limited budget. No shame in that. One forum post that stuck in my mind years ago was that 'Voigtlander lenses allow me to afford to shoot a M8'.
The Voigtlander 35/1.4 Nokton is supposedly based on the older 35mm Summilux, and I just love it. The Zeiss 28mm Biogon has virtually indistinguishable image quality from the Leica 28mm Elmarit I have, although the Leica is much smaller and has way better build tolerances.
If the emotional draw of a Leica lens on a Leica body is that strong, then just do it. Buying secondhand will allow you to sell with little or no loss at a later date, if you chose to. At least you'll have the experience and you can decide for yourself.