eh. that's not true. winusb is the built-in uniform USB access layer.. it's just that nobody uses it ... they all want to muck around with libusb and other 3rd party crap....
Ah, I stand corrected, I had never heard of this. I guess it's just the Linux heritage ported to Windows problem.
That said, I had problems with Atmel's 'official' libusb drivers (Jungo or something?) myself as well. Very picky about driver versions and blah.
Why don't you all take your PIC's and AVR's, and their development tools, push em together in a big pile , run over em repeatedly with some heavy trucks, douse the remainders in some gasoline and set them on fire.
And then switch to a nice ARM Cortex based machine like an STM32 cpu. They have a 32 bit processor for 32 cents now ... in SO package. You can't beat that !
http://www.st.com/web/en/press/p3444
I've done a bit of each and as far as the free tools are concerned, AVR and MSP430 are orders of magnitude easier to get working than ARM. Just bringing a toolchain from compiled to compiling running code is a chore, requiring linker scripts, startup code, libc stubs etc. to be provided by the user while this is mostly automated in AVR and MSP430 tools.
The ARM chips are powerful, cheap, and flexible but the variety means you basically need to do all this junk manually every time you use one, and especially for someone not steeped in embedded development it's not an easy task and certainly not well documented. The manufacturers seem to expect you to just shell out for the $500-5000 tools where it's all built in.
Oh and let's not mention the variety of JTAG gizmos, ISP protocols and software you might need to use to load code into them...
ARM is great, but if we're in 'how bloody hard can it be just to <insert trivial-seeming task> ?' territory, I think it will easily win that contest on almost every count as well.