Our Pentair MasterTemp 250 failed after 4 years (the warranty is 3 years). The pool cleaning company wants to sell us another Pentair heater, just this time a 400. I looked online and see that the online prices are substantially less than what our pool people want to charge us ($2,800 plus labor vs. $1,800 online for the unit). Before we decide, has anyone here had a positive experience with a pool heater that you would recommend. If so, what brand and model. Thanks.