Opinion question for all installing contractors:

Given a small retail space with two restrooms, one lavatory with a 0.5 gpm faucet flow rate in each, would you prefer to use a single, roughly 6 to 8 kw tankless water heater such as Eemax or Chronomite, or a 6 gallon tank type heater mounted above the ceiling? Co-worker tells me contractors tell him tank type is the cheaper way to go. I find this hard to believe given a tank type would require a platform, drip pan, expansion tank or relief valve, hub drain to run the drip pan drain line to, and most likely a trap primer to keep the hub drain from drying out. Not to mention you would have to perform this work on a ladder.

If it were you, what would you do?

Thanks to all who respond.