Dutifully reading newsgroup posts, I came across the advice that all parts on these furnaces, especially the electronics and the DC motor, are more likely to blow than on an old-fashioned furnace (the furnace being replaced, a late 70s Airco, had no electronics at all), and can be very expensive to fix. For example, $us 800 to replace the DV motor. Several posters suggested "go for the 10-year warranty".
It seems that in Canada, the standard is a 5-year warranty on parts (from the manufacturer) and one year labour from the dealer. My dealer said he'd get back to me on the prices for warranty extensions.
I'm wondering if any other readers have (or have installed) these furnaces, how old the installations are (I'm guessing that none are older than 5 years), what if anything has broken. What I probably won't get to know is how much it cost to fix, because everything will still be under warranty. Or is there a website which tracks the reliability of furnace components?