Based on ownership of 2 examples of Bessa R2a, one T and one L, I would say these cameras are generally well built, with good shutters, good vibration levels and surprisingly good center-weighted metering (even on the L, which is available for very little money). Bessa noise levels are noticeably higher, this is due to their design with a gray baffle in front of the shutter which is used for metering and which has to fall out of the way before each exposure. It is the presence of this baffle that makes the center-weighted metering possible.
A feature (not necessarily a problem) with all Bessas (except of course the L) is the shorter-base rangefinder compared with Leica M (examples of Leica M with the highest viewfinder magnification have the longest effective base, the Bessa T I believe has the longest base of any Bessa). If you were thinking of using a 90 mm f2 Summicron, 75 mm f1.4 Summilux, etc., this might be an issue.
The only thing I would call a problem is that the Bessa rangefinder mechanism is not as shockproof as a Leica. I would expect a Leica to survive, for example, a fall of 3 feet onto a carpeted floor without damage, a Bessa might not. I am told by my camera repairman that a Bessa rangefinder is a comparatively simple arrangement. Aside from that, I would say the Bessas are quite rugged (shutter, film wind, lens mount, etc.).
Regards,
David