Several years ago I made the switch to 5 strings, first a fretted OLP/Musicman then a Godin fretless. For the singer-songwriter stuff we were playing at the time, much of it in C, C#, D, Eb, and their relative minors, the extra low tonic notes were helpful. When the band grew to include more instruments, including some brass, just being able to get down under and out of the way was nice. These days I'm using those same basses in a piano/drums/bass trio and it surprises me how often I go low...maybe it's the pianist's left hand.

I like being able to get low notes higher on the neck too (eg, G on string five fret 8 as opposed to string 4 fret 3) as it may mean fewer position changes, particularly on the fretless where intonation when I move might be an issue. A two octave reach is easier.

Peace, Mooh.