Hi,
I have a pair of 12L2s. They are revealing, if not clinical, and very sensitive to positioning. I'm strictly neutral about them - not really the sound I like, but on the otherhand they are not a fatiguing listen in the way the speakers they replaced were.
Being honest, after the first week they were destined for ebay. Now, weeks later, the sound has lost its hard edge, the bass has improved, but they will always be a touch too clinical for me.
Don't know whether biwiring will achieve much, and might even accentuate that coldness. They can take a decent level of amplifier an CD player, too. I've got them matched with a Rega Planet/Nait5i, which sounds much better (as you'd expect) than the Rega/NAD C320BEE I had before. However, the Naim isn't the warmest of amps.
So, after all that, do I like them? Put it this way, I'll happily keep them for a couple of years.
There's a different opinion at http://www.tnt-audio.com/casse/quad_11_12_e.html