I don't think anyone is going to convince LG that the Lightning wasn't the better plane

, but just to sort things out for myself, if nothing else...
It's an interesting idea to compare each aircraft's role, but to others of the class rather than to each other. (I tried to base these at least partly on the discussion above.)
Bomber
Mossie: One of the greatest bombers of WW2
P-38: Apparently possible and certainly good enough to be comparable with some medium bombers, but not really known for it.
Winner: Mossie
Day Fighter:
Mossie: Successful in some roles, such as interceptor, but there were many better
P-38: Excellent, but few claim it was the best in the war. Probably surpassed in most roles by planes such as the Mustang, Spit, Fw190
Winner: P-38
Night Fighter
Mossie: Excellent, with demonstrated performance to prove it. Best allied nightfighter, possibly best in war...
P-38: Probably excellent, but without anywhere near the record of the Mossie
Winner: Mossie
Recce Plane
Mossie: Famously good, probably the best Allied recce plane
P-38: Excellent--but the US bought Mossies for this role, too
Winner: Mossie
High speed transport
Mossie: Very effective
P-38: Not really
Tagline
Mossie: Flew really cool pinpoint commando-raids-in-the-sky against Nazi installations just like in the movies
P-38: Shot down lots of Japanese planes
Winner: Mossie
Overall: Mossie
The P-38 was without doubt an amazing plane, but for me, the Mossie was in a class of it's own...