That's the new reference, isn't it? I have to admit, I find myself comparing a lot of things to the Quad 12L's.
They're completely different. I'm sure I'll get different results with some judicious tuberolling, but right now, in my amp, these are seriously basshead headphones. Almost PS-1 bass. And I don't find the Quads bassy at all. And you know that slight emphasis in the ...erm... emphasis region? The L3000 doesn't have that at all -- if anything, it has a slight midrange suckout (very slight...and maybe -- I might just still be getting used to the bass emphasis, and I'm hearing that as a suckout) with my current amp and set of tubes. It's hard to tell -- I've only had 40 minutes with them so far (Talk Talk's The Colour of Spring SACD).