I have a Jazz "frankenbass" that has a VM jazz neck on it, and also have a MIM Jazz. The VMJ neck is much slimmer in my hands than the rosewood fretboard MIM neck. The fretwork on the VMJ was much better than the MIM. I've not played a VMJ to hear the Duncan pups, but the MIM, while sounding like a Jazz bass, is a bit mellower sounding with it's stock pups. The tuners on the VMJ neck seem to be better with less slippage than the MIM ones, but this is all just a personal opinion. If I was spending the money, I'd probably go with the VM. But as others have said, try some out to see what you like the best. I bought both of mine off ebay and had to trust thatd I would like them, and despite the above, I like them both very much. As for the name, dont fret over it (no pun intended). I've got a new neck on the MIM now and it doesn't even have a name on it and I'm gonna leave it that way!
BnB