This seemed to have solved my problem on my HP Touchsmart laptop... the Netduino wouldn't show up in VS.NET 2010, even though it was showing in MFDeploy. I changed the driver as described, and voila, it showed up.
Unfortunately, now, while the Netduino Plus DOES show up, when I attempt to deploy, I get: "Error 1 An error has occurred: please check your hardware."
Sigh.
A handful of users running under VMs have reported a preference for the legacy MFUSB drivers. Here's a quick set of instructions on how to force your 4.2 Netduino or Netduino Plus to use the MFUSB drivers.
To manually switch to MFUSB (SpotUSB) drivers -- for special cases