S14 is lowest line of the three: standard plasma cells, the S1 and on up use the NeoPDP. It also loses some other minor feature or two, can't recall.
G10's advantages over s1 include extra HDMI input, THX mode, some more advanced consumer level pic control, possibly better OTB performance.
IMO, the main reason to get the G10 is to have access to THX mode.
OTOH, you can do a lot with any of the displays if you research SM offsets, let alone getting a pro level calibration, with colorimeter/spectroradiometer and accompanying software.