I've been an Alembic player for many years. However, after seeing Phil Lesh play his Modulus with Furthur, and coming across a Q6 at Bass NW, I made the plunge. I totally agree with your assessment of the Quantum series. They are amazing basses. Much easier to make sound good compared to the Alembic. Don't get me wrong, I still love my Alembic, but the Modulus stands up to it on equal footing.
Lover of Alembics, Seahawk Fan, 5 String Club #73