I don't own a 12FG, but a guy I fly with owns one.  I have a 12Z and a 14MZ, but my brother has been flying the 12Z, so I haven't touched it in about 2 years.

The 12FG is a great radio.  It does about 95% of the stuff the 14MZ does.  Has a good feel to it, but I wouldn't call it great.  Personally I prefer the feel of my 14MZ and there are a few little tricks I've learned with the MZ that I'm not sure the 12FG will do.  The 12FG does have servo grouping and such, so it will work well for the big stuff too.  The 12FG is a great radio, but that is a killer deal on the 14MZ.  If you don't mind spending the extra money for the 14MZ it has some features which are really nice, but you wont go wrong with the 12FG either.

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