In my experience it's easier and less risky doing it the agile way. You give them a 2-week sprint target. If they fail to hit that, then:
a. You don't pay them.
b. They're probably going to miss every other target.
If you paid the agile shop for everything they did no matter how crap, and withheld payment from the waterfall shop because quality control, then that's got nothing to do with agile vs waterfall, it's got to do with your QC.
a. You don't pay them. b. They're probably going to miss every other target.
If you paid the agile shop for everything they did no matter how crap, and withheld payment from the waterfall shop because quality control, then that's got nothing to do with agile vs waterfall, it's got to do with your QC.