I have been looking to replace my 40yr old boiler. I like the looks of the Ultra boiler but I don't know if I trust the cast aluminum heat exchanger. A good cast iron boiler you can get 40 to 50 years life out it but how long will cast aluminum last? A good cast iron boiler you can get 85% efficiency and the Ultra is like 93%. If the aluminum heat exchanger will only last 20yr then the added 8% efficiency isn't worth it.
Mark