A supplier employee here put one in his home, he says it sounds like a 747 taking off. Glass lined, 3 gpm. Limited life expectancy due to the glass lined steel tank, but I'm sure they will work well in the right applications. Not on par with tankless, but it looks like a viable option in some situations. It would be ay easier to recirc with one (than with tankless), but I believe the cost will put it out of reach for most. MSRP is up there.
AOS/State makes a good product, so you can't go wrong there.
Update: From what I have learned, AOS has addressed the noise issue with the blower. They are much quieter now.