I use one of the Leicameters. I decided on that after a lot of thought, handling a Voigtlander meter in the shop and the Leicameter of a friend.
Reasons for choosing the Leicameter were :-
It is coupled directly to the shutter-dial on the M3 and requires only one single push of the button to take a light reading.
The batteries are easily replaceable with hearing aid batteries (available in every pharmacist and almost all supermarkets with a battery section) and last ages. Thus the battery-'problem', isn't really a problem.
The Leicameter is very solidly 'part of the camera'.
The area measured by the meter can be seen in the camera viewfinder via the 90mm frame (that is perhaps less important than I thought, but useful).
The Leicameter is also easy to use off the camera with one hand, for example when using a viewfinder in the accesory-shoe. The meter fits in a shirt pocket without any problem, as would the VC meter of course but that is less one-handed in operation.
The Leicameter goes down to lower light than 1s at f1,4 with 21din film. Any less light than that I use a hand-held Lunasix in any case.
Both the meters can take a reading off your palm (add a stop) or off a piece of white paper (add three stops) if you need a quick incident type reading. This sort of thing doesn't replace an incident meter but is convenient sometimes.
Last, but definitely not least, the Leicameter has a proper needle-and-scale readout, so that you can instantly compare shadowed and bright areas of the scene and see directly what the differences are - within the limitations of the field of view. It's not a spotmeter !