Buy the first one you can lay your hands on. Now, Today!

It will not matter what model you buy because you will become infected with the Leica Zombie Virus and it will take over your entire mental ability to say NO. You will compelled to horde Leica after Leica from LTM to M's without meters to M's with meters.

Then wondering the streets as a full fledged Leica Zombie chewing on human flesh while documenting it on an M9.

There is no cure.