It is no secret that Leica's M5 rangefinder is considered among many to be the 'thorn' in the side of Leica's illustrious family lineage. I say a Thorn never hurt so good.
Many may not see it's shimmer behind it's bulkier flat frame-lines but it really has some great features which I think people overlooked at the time and still do today. Wiki tells it best
The M5 departed from the traditional silhouette of the Leica rangefinders, that had little changed since the M3 (1954). The height and width of the body were larger (H 84 mm x W 150 mm x D 36 mm), and the body heavier (ca. 100 g more than other M cameras). The folding film rewinding crank hides in the bottom plate. The self-timer arm and the field-of-view preselector (now on the M5 additionally with battery test function) are of the same design as the Leica M4 (1967). The M5 was the last M to feature a mechanical self-timer (duration 5–10 seconds). The M5 incorporates an improved rapid film loading spool design over the M4. The M5 has a rapid transport lever which winds the shutter and advances the film and the frame counter in one single motion, or in a series of shorter motions. A marker for the film plane is engraved on the top of the camera housing. The M5's redesigned horizontal travelling cloth focal plane shutter is reported to be the quietest of the M series.
It is no secret that it BOMBED, after only 33,900 units production halted and was replaced with a more familiar shape in the guise of the M4-P. Understandably Leica had a lot of pressure to make a change as the SLR popularity began to increase among consumers and professionals. Slow adoption by Leica users did nothing to help it's demise, essentially cutting short it's lifespan.
As time has passed the Leica M5 has increased in popularity with collectors, many looking for a cheaper opportunity to enjoy the Leica experience have opted for the M5 as a good 'way in'. There is allot to like about this camera, Bellamy Hunt's post about the M5 on his blog Japan Camera Hunter, is a good summary of everything which is great about this gem ...
In the hands the M5 feels solid, precise and machine like – more car engine than Swiss watch. The workman like appearance and larger build gives the M5 a heft that is reassuring. The one time that I dropped the M5 on my foot I was able to keep shooting, even if I had to do it sitting down for a while.
I think he sums up exactly my sentiments for loving the M5. It may be a beefy brother to other M's, but it's reliability, Leica mechanics and 'Real World' design make sense. Shooting with it is unforgettable, It really is a remarkable designed camera, which Leica thought through and implemented with assurance. There are no mistakes or wasted elements here, just a great camera overlooked and forgotten by most.
The Leica M5 is certainly to go down as a classic non event, it's popularity may rise and fall but it's ability to provide a great picture taking experience is undeniable and worth the purchase. So I for one am very thankful for the Leica M5, and proud to have used one over these many years. Leicas thorn it may be, but I say a little pain never hurt anyone.