The Noctilux is a hard lens to focus but when you get it sharp the images are like no other. Yes it is heavy but I don't notice the weight after shooting with a DSLR. Most of the weakness of the Noctilux can be corrected in software. If you stop down it sharpens up like the other Leica lenses but still has a chroma signature.
Leica M(240) with Noctilux