Plumber' Neck allows the putter designer to modify the to-hang and offset quite widely for an otherwise identical head (sans shaft).
Slight bend/Goose-neck/Double bend shafts achieve similar with a smoother look that may appeal to different users.
It really depends on what you prefer, whether you are likely to change the shaft (Plumber's Necks are much easier) and what your stroke and eye dominance is.
I certainly found that Centre-shafted putters suited me before finding out that they suited my Right-handed, left eye dominance,
It really is quite a search to find 'the one' and even then there will be days where that one will not perform. Good Luck in your search! It only took me about 30-40 'tests'!
