The Nikon rangefinders are very durable and built solidly. I wouldn't worry about them not holding up. In fact, I think they're heavier than they need to be. The Nikon rangefinder is part Leica LTM and part Zeiss Ikon Contax.
Like a Leica, the original S uses a cloth focal-plane shutter and has a shutter speed dial that spins when the shutter is released. Not ideal when using gloves, because the dial can drag on your gloved hand, slowing the shutter. Like a Contax, it uses the same mount and similar appearance. The focusing system is more Leica than Contax, although it has just a single viewfinder for viewing and focusing (like a Contax).
The early Canons borrowed heavily from the Leica LTM in their design and operation. They're fine cameras to use and not too expensive.