Well, here I come to ad my 3 cents to the end of the line. . . .
I'm not sure we can say which night fighter was best unless we first state what the criteria are. For instance-- an excellent plane brought in right at the end of the war, which saw a tiny bit of combat, but didn't have time to lay down a track record? Or an early NF such as the Beaufighter, which really "met the ox at the trough" so to speak, and slipped slowly into obscurity thereafter. Now, I don't know any of you on here, and I have not been privileged to access official data records, etc, nor taken the time to find out everything possible. However, Eric, I would like to ask you your opinion about the book "The Warplanes of the Third Reich" by William Green. As far as I know, the book is out of print, and I am privileged to own a copy. I don't know what to compare it to, but this is my source book for the Luftwaffe. No other book I have seen comes close to compiling a similar amount of relevant data and history on the subject in a single volume, along with photos, drawings, etc. The He 219 section in this book is about ten (big) pages long, and goes to great length to tell about the history of the type, and seems to indicate that the only two major problems with the type were bureaucracy and the deterioration of the war situation by the time it was pressed into service. Green states that it was exceptionally easy to maintain and service in field conditions, so much so that ground crews assembled six entire aircraft from spare parts and these were used operationally, though unofficially. The maneuverability of a night fighter is not very important, compared to for a day fighter, because it does not usually have to worry about mixing it up with single-engine types. Now-- imagine this, too. . . Just how fast could any of those German types have gone if it weren't for those huge aerial arrays they had to push through the air!!??
If you go based on what the plane was for the time it was introduced to night combat, I'm going to select the Beaufighter. In early 1941, it was faster than practically all the bombers Germany could muster, and there's just something about pulling the trigger for ten guns all at once. . . . and I dare you to find a sturdier nightfighter on the books. Well, the Mosquito might be as sturdy perhaps. One of the first to actually mount radar, the Beau I was a monstrous leap in the right direction, being lightyears ahead of ground-directed only fighters, or the Blenheim IF. . . . oo, enough said about the Blenheim. Bob Braham did manage to score his first night kill using a Blenheim, though, before switching to Beau's and eventually Mosquitos. I would really like to read an account of a match, day or night, between a Beaufighter squadron and a Bf 110 squadron. Comparing those two could be a forum thread in its own right. . . .
Also, don't forget that when the Mosquito NF II went into service, its top speed was only in the realm of 355 mph, more or less, which was hardly a healthy lead over the Bf 110F and G. How quick we are to forget the beginnings of the war as we enthusiize over the final year!
And while we're mentioning random thoughts, the Ta 154, though never operational, sure looks like it packed a lot of promise.
Let us not forget the F4U and F6F nightfighters, either. To be able to fly, navigate, fight, run intercept radar, and take off and land on a carrier at night ALL BY ONE'S SELF must have taken considerable talent indeed!