Mossie is serviceable in Air to Air combat, but not on the level of the P-38L or Typhoon.
When I'm in a P-38 only one fighter ensures my death, the La-7.
When I'm in the Mosquito (my most common ride) the La-7, F4U, Typhoon, La-5FN, Bf109G-2, Bf109G-6 and Yak-9U have the same effect.
The Mosquito is markedly more survivable than the A-20G. The A20 is tougher, true, but it is slower and far less manuverable. The guns on the A-20G are not nearly as good as those on the Mossie either.