Replace old siding with Hardie/fiber cement siding – Have you had it done?

We have a two story with the traditional brick on most of the house, but old (now sagging in some places) siding on the back and upper level of one side of the house. We've been thinking about getting it replaced for some time and wanted to see if anyone else had theirs done and how much they paid. I know houses are all different, but our layout is pretty typical/average.