Instant Hot Water Heater - Navien vs. Rinnai

Hi all, I need to replace my NG 50-gallon water heater and pretty sure I'm going to go tankless. I received two quotes:

199k BTU Navien Tankless NG or LP Water Heater - $5,975 (includes $3,500 of labor)

Rinnai RU199IN - $4,388

We have a 2 1/2 bedroom house with a washer and dishwasher. When I spoke to the plumbing company they said that Navien is like buying a higher quality car. Any thoughts on this? Thanks.