Killing tanks is better value than killing infantry. A full HP comparison is useless, any good player will use the loiter after the fight has already started or as they are about to push. And that goes for all factions
I'm not gonna argue that killing tank\vehicles is more important. What I was saying that UKF loiters tend to kill inf no matter what, unless you insta retreat there is always a chance to get your squads wiped. No matter if they are in cover, full HP or wounded. Overwatch AT while being strong, it cant kill tank in a one strafing run, unless tank is already almost dead. It cant kill inf, unless its almost dead.
As I was saying, that if we imagine there is AA unit and that the plane will be down after its first strafe, single UKF planes have bigger impact then the ones presented in overwatch. Main advantage why Sector Assault is over-all better ability, comes from the fact that meta commander has it, unlike UKF ones. 
But if you only compare those two abilities, side by side in the same conditions, UKF are imo have better ones.     
On top of that OKW will have AA no matter what, UKF needs to devote popspace to it. Sector Assault is by far the best in any realistic scenario.
Schwerer and MGs are not the AA counter, its RNG soft counter, they might insta gib or might not do anything. If you are facing opponent who always use either recon or any other air based abilities and you want to properly counter them, even as axis you need Ostwinds\AA HT, everything else wont give you great results. 
P47s are wildly unreliable, might get you a KT kill, might miss every single rocket. Also has collision issues on a large number of maps
Its unreliable, but as I was saying its by far the hardest one to counter with AA, thats why I've mentioned it.