I realize I am late to the party here but as has been stated, absolutely no comparison between PPK and NDM. NDM is pure honey sweetness with a very distinct flavor profile all of its own. It has no tartness or lemon flavor whatsoever. PPK, or lemon meringue, has a very distinct ceamy sweet lemony flavor profile. It is an excellent mango. Only drawbacks in my book is its vigorous growth habit and small sized fruits. If you have the space it is definitely worth growing.
Now, comparing PPK to its seedling LZ. Really no comparison to me. LZ has a distinct sweeter, more orangy citrus overtone to it with a hint of lemony tartness versus a true lemon tone to that of the PPK. To me, for LZ, think of a really great orange, say a honeybell, add a portion of meyer lemon, and mix with a base of "mango" flavor. Yes, this may be a little cavemanish but that is how I would describe it in a flavor profile way of thinking.