Which filter holder system w/ 14mm?

VWFC wrote:

any advantage with the CPL at the back (closest to the lens) vs in the front like the old holders and Lee?

A filter closer to the filter thread can be built to be smaller, which also can make the filter cheaper (or better at the same price point). Moreover, a CPL close to the lens actually makes for a neat light seal, prohibitting stray light rays from entering the lens from the side. When the CPL is attached at the outmost position, this usually doesn't create a fully sealed system with the holder and other filters, so there is a risk of stray light lessening the effect of the CPL and/or creating visible reflections from light bouncing between the back of the CPL and the front of the filter stack.

In my opinion, the major disadvantage is the use without an circ polariser. In designs like the Formatt Hitech holder, the CPL is screwed into the adapter plate, which in turn is used to attach the other filters. If you want to shoot a scenery with grad NDs and NDs, but without a CPL, this requires you to take off all filters, the holder and then unscrew the CPL from the adapter ring. Then you have to attach the adapter ring, filter holder, and filters (unless you can keep them safely in the holder).
A system that attaches the CPL at the outmost position, allows for easier removal of the CPL with all other filters remaining attached.

When I use my filters, I also use a CPL in the majority of cases, so the advantages of a CPL attached nearest to the lens easily outweigh the disadvantages.