The IIIg is still pretty compact and has a very good finder. It is an exceptionally well made camera - almost a mechanical work of art - as much so as earliest M bodies.
Originally Posted by Mewael
The Bessa's are all very well made, reliable, and durable enough for most people. The Bessa R is fairly compact and it is light - the L and T of course more so. They are lighter and more compact than Leica M's. Not sure if they accept all collapsible lenses. The Bessa bodies (with finders) have about the best finders I've seen - they best early Leica M models.
I don't have too much CL experience, but they seem OK - not that small or light - many need servicing.
The Leica IIIc_IIIf series are decent cameras, with a so-so, but usable 50mm viewfinder.
The other Leica III series have usable finders and only for 50mm frame lines. Their finders are pretty poor by modern standards and there are other bottom loaders with better finders. The Leica external 5cm finder is small, and a real work of art - fantastic on a Leica III series.