The choice is meter or not, simple. They are both very capable lenses.
I don't understand why anyone would not use a BP M3 or an MP3. They are not one off's and their value although high is not that much more than a digital version.
If anyone has to question whether or not they will use it or not then IMHO they shouldn't be buying it BUT I do understand that there are people who just desire things to own and look at.
I'd have either happily but I'm not a fan of M3's because of the finder so I'd prefer the MP3.