I'm in the process of deciding which furnace to get to replace my
existing furnace which is ready to die. I've been told that high
efficiency furnaces are not really worth it since they cost more up
front and they cost more in repair costs in the long run so in the end
high efficiency vs normal efficiency will have cost about the same, but
the high efficiency will have broken down more often due to it's
complexity. This makes sense ... but I have one more quick question.
Are dual stage furnaces quite complex and prone to break down also?

I've thinking of maybe getting a 80% dual stage furnance which would be
a bit more efficient than a single stage 80% furnance. But I'm
wondering if it's worth it. Would a dual stage 80% furnace be as
complicated as a 90%+ furnace? Are the parts just as expensive to
replace/repair as a high efficiency furnace? Or in other words should
I stay away from dual stage furnaces for the same reason I would stay
away from a high efficiency furnace (high repair costs, higher chance
of break down).

Thanks,
Harry