For me it depends on the shape I'm playing and what strings I'm playing.
For example, If I am playing a shape that goes from the E to the G string, i use the floating thumb method. If I am playing a shape that is on the D/G strings, I anchor the thumb on the E string. if I am playing a shape on the E/A strings, I anchor on the neck pickup.
Guess it is just what I'm comfortable with - find out what you are comfortable with and use it.
For example, If I am playing a shape that goes from the E to the G string, i use the floating thumb method. If I am playing a shape that is on the D/G strings, I anchor the thumb on the E string. if I am playing a shape on the E/A strings, I anchor on the neck pickup.
Guess it is just what I'm comfortable with - find out what you are comfortable with and use it.
