As you can see, it's a love/hate relationship. Some people hate it - others (like myself) love it. After purchasing mine, I almost never shoot my M3. It is a better fit for my large hands and the built in meter is so much nicer than using the Voightlander II on my M3 - which is always coming off as I walk and shoot. The spot meter is refreshing to use - and for me, the best thing about the M5 is that it (the 3 LUG variety) has 28mm finder lines in it. That means no guessing when shooting my 28mm. That's worth the cost of an M5 by itself. I have had ZERO issues with the meter showing up on negatives or slides and have never heard that from anyone I know who shoots an M5 (not to say it didn't happen).
If you don't mind - or like - the bigger size, built in spot metering and 28mm frames, the M5 is the rangefinder for you!
Let us know what you decide.