The 8FG is definately better value than the 7C.
The 7C will only allow S.bus usage via the R6203SB receiver. Then you better have everything S.bus.
The 8Fg allows the use of every FASST Rx for airplanes. That alone is flexibility.
The programming functions in 8FG is very close to 12FG while 7C is nowhere near that.
Consider also that production of 7C has likely stopped (6EX is stopped and only stock is sell out and unites kept back for warranty supply), the 8FG will give you better long term investment
just my humble advice.