Well the WC near C12 is the nicer of the 2 but the other posters are right - its more about Proximity. Basically the C12 club is the 'new' style with wood paneling, segmented small rooms, etc. The F/G club is the last hub club from the 'old' style. The 'old' style is basically a large open grey room with a TV in one corner and a bunch of cube-like slots. Very boring. Both serve about the same kinds of snacks.

The Rule I use:
If you have a flight in A,B,C,D, and G gates greater than about G15 go for the C12 one.
(unliklely you'll have A or B with a HNL flt though but for future reference they are a long walk from everything).

If you have flts from E,F, or G gates less than G15 - go with the G/F club. Be sure to allow a lot of walk time for E or F gates.