The boxset is disappointing. It is basically the latest BR movies all wrapped up in a wonderful box. Beyond that there is nothing new. No extra material besides the found in previous releases of the saga (e.g. Terminator 2: Skynet Edition).
I would only recommend it if you have been looking for a great box for your Terminator collection which can sit proudly beside other boxsets, or if you don't own the movies already and wish to save some bucks buying them altogether. If not, better stick to your old movies and wait for a decent boxset which has something else new besides the box (at least some extra pictures, booklet or redone dvds menus).