We had the same pool heater installed in 2008 and we had it replaced last year.

We chose a Pentair heater and we have been very happy with it so far. Installation cost was $3100 which included tax, install, etc with a 3 year parts and labor warranty.

I own a swimming pool company in Florida and we have been using the Hayward H series low nox heaters for years with the least amount of issues. As you said, they all have negative reviews and they all have their issues, but those have served us best.

We have been using Jandy heaters for 30 + years now even when they were known as Teledyne-Laars heaters years ago.
They all have there share of problems as do the other brands, but the new models, such as the Jxi have been great for us.

No matter what brand you choose, first you must make certain your gas line on natural units, will provide the adequate supply to operate it correctly. Gas line size is paramount when choosing a heater. A 400K BTU is best for say a 20x40 pool, but if the gas pipe is too small, it won't function properly and it will fail early.

Propane models too must meet gas/fuel parameters.

I have many times replaced large natural gas heaters with smaller models based on the gas pipe size. Yes, it will take longer to heat, but it will work properly.

Also equally important is managing water flow through a heater. Too much or too little water does not allow the heater to work properly and can cause premature failure. Flow must be balanced. All the manufacturers have a max and minimum flow rate.

Of course properly balanced water chemistry is important in preserving heater parts.

Most heaters will last about 10 years.

Did a lot of research after my Pentair crapped out a few years ago.

Settled on a Raypack 400k. I swapped out one for the other then had the gas guys come out to adjust the regulator as needed.

Love the heater. Easy to maintain, easy to winterize. No issues. Fires right up each spring. If this one died, I'd get another.