As an alternative to fiber cement, I'm looking at LP Smartside.  The designer/builder who I have working on my plan really likes the product - much lighter and less brittle than fiber cement, a little less expensive.  Anyone here have any experience with it?  Installs much like fiber, comes in 16' long planks - very nice, since my house is going to be 72' wide!  Available pre-finished, etc.   I keep thinking of the masonite siding horrors - but then I'm hearing that fiber cement is having issues in my part of the world as well - mainly at joints/cuts where moisture is being absorbed, boards swelling etc.  Is that all poor install, or is the product that touchy?

I have installed many thousands of square feet of both fibered-cement lap (brand name not stated) and OSB lap (again the brand name not stated).  My company was one of the first to install the #1 brand fibered-cement lap in Kansas.

Both products are good products, if they are installed correctly. 

Both must be end-gapped correctly to prevent problems with expansion.  The amount of gap is directly dependent upon the ambient temperature at the time of installation.  The fibered-cement is more problematic about proper gap than the OSB lap.  If the ambient temperature was below 50 we would gap the butt joints using a 16 penny box nail.  Everytime a stick was hung we would drive a nail at the end to be butted against.  When the caulking was to be done the nail was removed and the caulking done.  OSB lap was done very much the same way.

The fibered-cement especially, needs a solid substrate under it to prevent impact damage.  We never installed any lap directly to the framing.

Again, both products are good products when installed correctly (attachment, caulking and painting). 

We used the pre-finished fibered-cement on one project.  The product was at the request of a customer with the understanding that they would be assuming responsibility for the product maintaining its color and seal.  Another problem was that there was no caulking product to color-match the siding and I do not know if this has been addressed by the manufacturer or not.

Water absorption can be a problem with any siding problem if not sealed properly.