Had the boiler for 2 seasons now. It's a great boiler. The IQ system works great, it's quiet, and saves about 40% on gas over the old Weil-McLain we had. Remember: a boiler is part of a system. It must be installed as such. Any installer that simply moves the old, slides in the new, and calls it done is a total hack and should be fired on the spot. There are very special considerations to be made for some system types when used with a cast iron boiler; for example, radiant slab and cast iron radiators. These run at lower water temps. A cast iron boiler needs to maintain at least 140 degree water or the flue condensation will rot the boiler out in very short order. The ESC can run at slightly lower temps, such as 125-130 degree supply water. These days, most boilers are pretty great. Unfortunately, most failures are caused by incorrect installation, and the boiler gets blamed. My advice: do your homework. Learn how the system works. Read the installation manual and question the installer. It's your money! If you want the boiler to last 30 years, make darn sure it's actually installed the way the manufacturer specifies. Because if it's not, it's YOUR OWN FAULT. So many negative reviews. I know of 17 Burnham installs in my town, all done by the same installer, who actually does things right. It may cost a little more initially, but you won't have issues later. If those 17, 17 are still working perfectly. The oldest 3 units are 27 years old. Install, install, install. Don't blame the boiler just because you hired a moron.