109G-6 is probably the most fun plane in the game to fly IMHO. Great flat turns, does OK in the vert if you've gotten your E up, and does some great rolling if you keep the garbage gondolas off.
I also prefer the G14 over the K4, just because the K4 seems too much anti-grav for my taste. I tend to get timid and just hang on my prop waiting for a stall instead of being aggressive and forcing pilots to make mistakes.