I am building a new house (Mid-West - Near Chicago) and I am trying to
decide between natural cedar clapboard (primed and painted) or a
synthetic such as primed and painted cement fiber board (i.e., Hardi
Board). My builder is strongly discouraging me from deciding on
natural cedar. I have also asked all of the building suppliers in the
area about natural cedar - they all look at me like i am crazy to want
to use natural cedar. The collective opinion is that natural cedar
will only look good for 5 to 10 years (regardless of paint job).
After 5 to 10 years, they claim that the cedar will show serious signs
of decay.

Is this an accurate description considering the cold winter climate?
I am concerned that they are pushing me towards a solution that may
have a higher profit margin (or some other motive).

What kind of life expectancy should one expect from natural cedar?

Thanks in advance for your input.