IIRC, it climbs better at most altitudes, accelerates slightly better (by a margin of 1 second or less), and is equipped with the 2 weapons that have, argueably, the flattest, and thus the most desireable, trajectories in the game. Not to mention its visibility is undeniably superior, and its nose is not made of a glass/cardboard composite. That could be why it's perked.
The 14 has only half the WEP time of a K-4 and has no significant climb rate advantage at all. It's fragile as any Spit. It may have 2 Hizookas, but it's one of the worst, unstable weapon platforms in the game. It's prone to some nasty stalls at slow speed. Roll rate quickly drops to almost zero at high speed dives. Speed & power really shine only at very high atlitudes, at usual AH combat altitude it's slower than the ususual suspects.
And last but not least, it has no "unbalancing impact" on the arena whatsoever, despite the low perk price, it's about the the rarest AND least successful perk ride we have.
In AH, it's a difficult to fly, overpowered Spit. In some ways, it's more a challenge than a gratification
