I would look to get a used Peavy or Carvin to see if you like a 6 or if it fits with your music/band. I found the upper string is just not used that much in regular grove oriented music. More progressive music it's good for soloing & chordal work. I found it not as satisfying as a four or 5 string.
Just my opinion
+1. I have 2 sixers that don't get used much. it's nice when i do the occasional jazz gig for soloing options, but i've come to realize i'm a 5 string dude at heart.
