i like the HS, as it's the only one out of the group that lets you isolate a single coil. i find the neck humbucker a little too muddy and dark and the single in the neck position sounds great. it also allows for the inner coils sound that so many people like on the HH.
but the volume drop off is silly. just fix it already.
i know the reason why the volume drops off, but there are basses out there that mix humbuckers and singles with no volume drop off... the passive Tony Franklin is an excellent example.