I also use a stand alone HDD-recorder : The AW16G Yammie.
After all tracks are recorded I send the mix to PC for mastering.
Pro's for HD-recorders :
Independent
Easy to transport/move
Just push button and go !
Very quiet (no fans)
huge capacity of HD
dedicated DSP's (need no CPU-load)
real faders
very stable/reliable
no (expensive) plugins needed
... etc.