We have been using Sikkens waterbornes now for over a year at the body shop I work at. All shops in California need to be changed over by the end of 2009, I believe. We changed over a while ago since we knew it was coming and to avoid the big rush.
Our paint shop seemed to have teething problems for the first couple of weeks and slowed down, but were back up to speed shortly after. Water based paints flash quicker, we can paint one or two more cars per day than we previously could. As for shelf life, we recycle our paints as our shop runs a pretty tight ship, so I can't really comment on how long it lasts in a container.
