They are all equally cancerous, regardless of which faction they are from. No ability should be able to do so much damage without any immediate counter (and please spare me with AA, as long as AA is so unevenly distributed). It can deal lots of damage if you don't react, but give the player the ability to react...
On top of that, (atleast the UKF one) the airstrikes are dirt cheap. 120 munis is nothing in coh3.
Edit: These loiters are always worth it, even for single vehicles