Both are generic driver.
1) If you use VC++, I think there are more examples with Microchip's custom driver and DLL.
2) libusb-win32 device driver does not support Vista 64. Microchip's seems to support it well.
3) libusb-win32 device driver supports isochronous transfer. I do not think Microchip's driver work well with isochronous transfer based on the testing last time.
4) libusb-win32 is open source but has not been improved for a while. It may get some updates this year according to the author.
5) libusb-win32 has the counterpart libusb for Linux, Mac OS X, BSDs and Solaris. So it has some advantages for cross-platform projects (mostly in gcc).
6) libusb-win32 has also the filter driver, which is not working for Vista and may cause problems. But it seems to work under some situations so there are people using it.
7) Take note the license restriction of Microchip driver, it is only for Microchip product. libusb-win32 is GPL/LGPL so some restrictions may also apply as well but it is not limited to Microchip product.
post edited by xiaofan - 2009/05/15 04:32:32