When I was in KwaZulu-Natal last year there was occasionally some flare on my M6, but to be honest, I've never thought it a problem. The finder on my M2 seems much brighter.
Either way the cameras and lenses themselves are so light and easy to use I have always just excepted it as being how it is! I started using screwmount Leicas years before the internet, and so have never had a problem with on-line reviews!
I suggest you go to a camera shop and just try one out. The only problem with that course though is that as soon as you hold it, you'll have to have it!