The F is the nicest to fly... It's an absolute pleasure... but as far as brute force goes... The K4 cannot be beaten.
The difference between the G-14 and K4's turning ability may not look huge on paper but it is significant in game. I notice a big difference between the two and I will up a Gustav if I need a quickish plane than can really mix it up in a good fight too.... Base defence against a CV... the Gustav is perfect if the cons know what they're doing.
If they're seals I'll just up a G-2 or G-6 and make use of the 200 20mm rounds. If they're smart and I need a bit of extra grunt to keep the carrier steel honest in a fight, I'll go with a G-14.