Right Wayne, The modulating burners go from something like
18,000-190,000 Btu for the Takagi, My little Bosch does something like 30000-117000 Btu.The Energy Factor is a True rating nobody making a tank wants to discuss, and few consumers are smart enough to ever check, that is your true rating. Plus rated unit Efficiency. The true tank standby loss is excessive and pipe heat loss im sure not included as very few people are smart enough to install thermal couplings on there water heaters.
Now consider tankless 30 year life, no tank to rust out, its all copper pipe.
Now consider tanks scale. Rated efficiency is downhill from year one, I just removed a 20 yr old tank with 12" of hard scale, now that lowers efficiency alot, tankless do not build heavy scale, but should be delimed every few years.