I installed a Noritz tankless a few years ago, even though our 50 gallon water heater was still in service.
I chose Noritz because they are made in USA, in California. I got a recommendation from the facilities manager at my company.
The problem with tankless is up front cost. They cost more and the exhaust flue is generally stainless steel which is pricey.
You may also need a black pipe gas supply line upgrade, which can be pricey as well.
Noritz came out with a 50 gallon water heater replacement that could use the existing exhaust, saving quite a bit.
It was also able to use the existing gas supply line.
The Noritz is probably the most expensive, and is top quality.
You have to wait for hot water, which I don't like. After the 1st shower, there is no problem.
Beyond that, they are great.
I won't go back to tank style water heaters.