eagle, you can replace the devices with 'standard' devices if you want/need to. You do not need to stock these devices for service work.
also, I don't know the cost of the material, but what is your time worth? is the time savings worth more than the extra material cost? and not just the time on the job.
But say you can finish an hour earlier each day, wouldn't it be nice to spend that hour with your kids? your family? at the local nudie bar?
Personnaly, we buy more expensive items all the time, so long as they save us time. We've been using Arlington 38AST's for years, even though they cost us 5 times the price of a standard MC connector. But the labor savings is much more than the cost of material.
I have a good friend in Arizona that does custom homes, i'll talk him into trying this product and let me know how it works.