Although internally they are different, in terms of expansion, they can be considered the same. As said, you can save a lot of dough by sourcing switches, pots etc. from electronic stores instead of buying the overpriced Robbe items.
The computer on the FC16 is worth having if you have a lot of models, as it enables you to store servo reverse settings etc.. Most of the built in mixing is a waste of time on subs, as you usually end up having to mix on-board the model itself anyway (e.g. x-tail).
Both FC16 and F14 can be converted to dual 40mhz/2.4ghz use, so you can also use the set for aeroplanes and/or surface craft. I used a Corona DIY kit to convert mine.