Its not exactly what you fly, IMO. It is how and who is flying it.
Anybody can go to 20k for a 5k fight and pick...
But not anyone could run into a furball in a Spit14, and come out alive...
Not to mention Spit14 better at higher altitudes. So what exactly is your plan on using this plane?
my one flight last night consisted of me flying in at 17k, picking one enemy, then defending a Vbase at around 5k and killed 4 more at approx that alt. it flies like a p51 and 51s can do well at these alts also. the spit14 also keeps up with 51s at this alt like a spit16 would and is more stable as a firing platform than the spit16. im not just going to pick with the 14.
(also... yes, not anyone could run into a furball in a spit14 and come out alive but its the exact same with tempests, f4u4s and f4u1cs). you cant go into a furball in a tempest and expect to actually stay there long without dieing. a spit14 has more of a chance than the tempest.