No demo yet, but I do need to do one as I have two Franz basses (I have a fretted 5 too).
My bass is a standard Sirius with upgraded maple top, whereas the RG model has a Rheingold pickup and no volume control.
All Franz basses are chambered and use thermo treated woods, so they are really light and very resonant. My fretless is 8.25lbs, so nice and light. It really sings, has no dead spots on it at all, and is just a joy to play.