I've tried a few when I've been over in Carlisle chatting with Chris and co.
You really do need to try one as they have their own sound and feel depending on the woods used.
Whilst they are all the same design and have the same circuitry and pups, they do have subtle differences. As far as the generic sound goes I agree it is fairly "middle ground" but thats not necessarily a bad thing for sitting in the mix, and no different to many other basses I've tried - e.g. Yamahas. I think the circuit is designed not to be too extreme and enhance the natural tone.
Generally I've always found them to have a very clear sound with a sweet top end.