Well for my taste, I prefer the series (there's nothing wrong with signature electronics)because of the separation (bass/treble) and if you have a series with the right amplification..You Will Hear a Difference. Absolute total control of what you want to hear, and after a while you'll be able to dial any tone(s) you want within seconds and you'll bandmates will be pleased.I have never owned a signature bass so I cannot compare it against the series (that equals apples-n oranges). I just know after hearing the series live, that that was the way to go. Imagine this..you are sitting in front of two speakers, Speaker A pumps out bottom only and speaker B pumps out treble and you can add exactly what you want to come out of those speakers (yummers!!) With the series II you get an extra volume potentiometer to control overall volume (double yummers!!)You ever hear Stanley's axe live?!! (i'm getting excited!!Give me a second to compose myself) The bottom line {IMHO} is that all Alembics are all good, all that and it's like saying hmmm..what kind of Rolls Royce do I want. If you ever get the chance to aurally compare the signature and series you will dig the tones and feel the force Luke!!