Difference between NEC code book and handbook (who is the target audience?)
The code book alone is pretty hard to understand, it's 900 pages and all written in legalese.  The handbook is useful, it adds some non-legalese clarification to the NEC itself.  Mike Holt's materials are great, they are made to make sense of the legalese, and they're popular for a reason.
However none of the above are in any way a design guide or an installation guide.  In my opinion a DIYer is better served with the many DIY / residential wiring books available, and for anything beyond the bare basics, get your work inspected.
Note that most of these books are revised for each code cycle, so your best bet is to buy the revision that was written for the code revision in effect in your locale - the 2014 NEC in your case - even if it's no longer available new, it's easy enough to find prior revisions of these books used online.