Hardi Plank siding from James Hardi has a new and improved product line out.  The most significant improvement is that there is now an option to order the siding pre-finished.

One of the most notable changes I have seen is the new installation requirements which require the use of a flashing tab at the end joints of the siding.

 
Sample Image From Online Specifications. Check
Hardi Plank Web Site For Full Specifications

In the past they recommended caulking of these joints which always seem to peel and separate.  While this can often be controlled through back-caulking, (where you apply caulk to the joint prior to installation of a plank and then after thus sandwiching the sealant), there is always the potential for the caulk to separate, peel, look awful, and allow more water to reach the moisture barrier.  This new detail should work better although I do not have faith that most tract builders will do a good job implementing it.

Check out the new specifications on their web site at:
 
http://www.jameshardie.com/