I played a sixer for a couple of years...
Some creative chordal and harmonic possibilities open up with the high "C" string.
The huge neck used to hurt my hands and wrists, though...
Also, string spacing is so close that any serious slapping is pretty much out of the question, at least for me.
It went back to where it came from (my son)...
Been using a Precision tuned BEAD, and my Longhorn tuned standard for the last month or so. Works better for me, although it takes a little practice at first.