well first off water based paints are not new. they are a marketing ploy to get pro shops to start using them. they take longer to cure are different to spray and not very good to use you are in the repair buisness.
one example of the crappy sides of water based paint is the dodge neon. only one year used the water based paint and nearly all had defective turn out. you might notice the ones with the paint nearly peeled off??? i read this in a autobody magazine.
from the looks of things the us is giving breaks to shops using voc free coatings. they are certifying shops through various programs being green friendly here in virginia. all new body shops here are now having to conform to hazmat regulations, minimum equipment regulations, local voc polution regulations and so on.
the good thing is when you start a buisness and conform to the demands of the voc free side there is less investment. often times you can get away with having fire suppression in your paint booth. and you can throw trash in regular dumpsters. wich is good. if your competion rats to the epa that your doing this you can get huge fines.