first, hardi is NOT maintenance free. It will last much longer in my opinion that siding, but has to be painted and cared for almost like wood. hardi is fire retardant, insect free and hail and other flying obstacles free. Its good stuff, also a hard ball batted into the siding will cause it to break and crumble to an extent. It does come in a nice wood grained look. This would be more expensive in labor and material than vinyl siding.
Vinyl siding has its pros and cons also, I know you are aware of them.
Secondly moving a home. the main problem will be racking of the house, cracked floors and walls, and things that might have been a 90 degree angle will not be any more. Much depends on the professionality of the movers. Good luck.