I'd like to know how many of the folks that sell mechanical equipment for a living (no offense to DIY's and homeowners but interested in the pros here) have an on demand water heater in there home.
J

Not sure I count but no, and I have little good to say about them, especially the electrics.

I won't rule them out entirely in certain specialized circumstances, but I believe the wave of the future is a manifold very near a conventional storage tank with skinniest possible PEX lines serving each or no more than two (such as his / her vanities) hot water loads.

You're a pro in my book Curt

I don't have one, and will never have one. It's completely unnecessary and far too expensive.

We don't seem to be in favor of them. Who has -First hand- experience with the Pros or Cons.
J

One of the main problems with them, is that they clog up with minerals quickly, and need to
be degunked or else performance drops dramatically. 

Anybody have first hand experience?
Any pros use 'em?

Any air in piping will cause them to go into hard lock out , in new construction I have seen a flux happy plumber gum one up pretty good .
for higher demand situations ( ie large homes ) where multiple units are required it can be a real pain , in those cases you really need domestic headers so allot of times retro is near impossible