I have to buy a new propane heater for our spa. The PB is trying to sell us a Hayward (400,000BTU) heater unsurprisingly as he is a Hayward dealer. We would benefit from the increased warranty period due to all our equipment being Hayward.

Our gas installer heavily recommends the Sta-Rite SR400LP. He seems to have less of a vested interest in the brand I choose as he would not be supplying the heater, simply installing the one I purchase. However the Sta-Rite is Low Nox and from searching this site I see the pool builders and repairers recommend staying away from Low Nox if possible, though I am not sure why.

I also see that RayPak's seem to get the thumbs up and Hayward's generally not so much!

Your help/reviews and especially comparisons would be greatly appreciated, as I have to make the decision this week before family arrive from overseas.