1) house was built in 1993, fist owner. Since it was built in 1993, the codes were different. For me to install a new tank HWH would require the company to install a square cement wall around the unit and deepen the ditch (it's in a "half" crawl space with 6' height). The existing unit is 48" and newer units are taller. BLUF: to replace with a .7EF HWH, 12yr warranty, do the install with construction will cost me about 3k and no 30% Fed Credit.
I've had 3 companies come out and they won't touch it without the modifications. My 3k quote was the low quote (I won't even suggest what the others were). From all the research I did, the Nevien consistently hit the top of the charts as it relates to EF and warranty (my 2 criteria). I provided each company with my research. I got responses from my research: from dumbfounded - never heard of companies like Navian or Noritz or Paloma ... to stunned happy surprise that a consumer did research. My research was done not on company market fluff, but the governments Energy Star program. As of right now, there are ZERO tank HWH's that qualify for the credit.

2) for 3.3k, I get a new Navien NR-210A (bells/whistles), .98EF and installation of circulation T's at the long runs on external circulation, 15/5yrs warranty ... and the 30% Fed Credit. To me it was no brainer. More efficiency, less cost overall after credit.

My math:
Standard tank: 3000.00
Tax Credit: 0.00
TOTAL: 3000.00

Tankless: 3300.00
Fed Tax Credit: 990.00
State Rebate: 199.00
TOTAL: 2111.00

Delta: 889.00 savings going tankless, + reduced gas costs.

That is an outrageously expensive water heater.

Did they gold plat the inside of the tank for corrosion protection?

I'm not a plumber, but 3 separate companies wouldn't touch a normal tank install without doing the modifications. Tankless: mount, hook-up, done. (I have a 1" gas main into the house, made it easier).