Lafiel Couldn't find anything about the P-61 to compare to but from what I can tell there were only about 1/12 the amount of P-61s as P-38s (P-38 had a larger impact on the war), P-61 was generally a larger and somewhat slower aircraft, and was a night fighter rather than escort and interceptor. Pretty different roles IMO, the only real similarity is the twin booms. The P-38 wasn't good because of maneuverability, it was good because of accuracy and speed so I don't think it's fair to say that the P-61 is simply better.
KrankysFirebrand48 The P-38 was actually horrible in the European theater and only really had success in the Pacific where it's design made sense. So I don't know if it makes any sense to compare a Pacific heavy fighter to a European light bomber. The planes were actually similar in speed but that doesn't mean much because of the differences in maneuverability and general role.