Both HardiPlank (lap siding) and HardiPanel (panel siding) continue to be carried by Home Depot and most lumber yards here in the DFW area as well as their other cement-fiber products such as soffitt and backerboard. HardiShingleside (shingled siding) is still on their North American website, but the cement-fiber roof shingles seen to have disappeared from all countries on the James Hardie site. Last fall, a local TV station in Dallas carried a story about these roof shingles on houses in one neighborhood which were chipping at the exposed edges - a comment was made that perhaps it was due to the Texas heat. Following was a warning post on the board; as I remember, the differences between this manufacturer's building products became rather blurred as others joined in.
I used HardiPanels on a cabin nestled in the East Texas woods in 1994 to gain experience with what was then a new siding material to me. In spite of my deliberate abuses (placing it in contact with the ground and not painting it for a year - which would, of course, void the 50-year warranty), it held up well, still looks good, and didn't delaminate at the ground level as I expected. I was impressed enough to use it for the whole house last year.
If the corners and top-sheet edges are not protected during shipping it can be chipped. When using a large hole saw, it can delaminate and separate if not supported from the back side. If cutting out for windows, etc., a cross-grained strip less than about 5 inches can snap if bumped before it's placed. Slanting nails to hit a less-than-perfectly-aligned stud can also cause separation at the edge.
A diamond-tipped saw blade will last through the project, but not necessarily the saw itself. You can try disassembling the saw and cleaning out the bearings often, but the abrasive dust will eventually damage the bearings.
There are lots of opinions on the fastening method. Some prefer to pre-drill for nails; one old pro prefers manual hammering to avoid overnailing.