The necks on the Squier J Mascis are really great. I echo everything that has already been said regarding the quality and non standard pickups/bridge.
The VM Jazzmaster is a great instrument in it's own right. The pickups sound great to my ears and set up with a bit of care the bridges are fine. You have to kiss a lot of frogs though to find the gems. I tried a fair few before finding one that was well built, had no finish flaws and sounded great. Although maybe I'm a bit too picky when it comes to this. A lot of the ones I tried that had problems could probably have been solved given a good set-up.