Jeff --
As much as we appreciate your contribution to the world of CNC in general, we also have to realize that everything you say here - besides being obviously biased but also good willing at the same time - is not exactly to the point. Let me explain who exactly is this whole "Windows, parallel port, mach and 64 bits" is all about:
1. People running their machines from their "main" PC - typically found in a home office, living room etc.
2. People who spent no more than a fraction of the cost of a "real" machine
3. All others who just don't want to spend an extra $150, regardless of benefits.
No matter how far you look down the road, a parallel card will always cost $10 or less, while a SmoothStepper will always be several times more, $150 or whatever. By definition, a niche product like the SS will never ever reach commodity pricing.
Today already, but even more in the near future, small machines are bought and used by hobbyists for almost the price of a printer. For these hobbyists, cutting some parts every once in a while is perfectly fine with Mach and the noisy, bad, limping parallel port. Trying to convince such a hobbyist to buy a SS is like trying to tell grandma to buy the $35,000 Buick and not the $25,000 one because it has more horsepower and chrome wheels, too.
And one last thing. Unless you start a SS vs anything-else forum post with something like "for a little extra money", your opinion risks being summarily dismissed for originating from a biased party. Again, regardless of the SSs benefits.
By the way, I have one and I love it.