Just got my '56 a few days ago. Basic streaming works, the Liquid preamps are usable as plain preamps (no funky emulation, but who needs that). ADAT ins 1-16 work, external preamps sync'd to the Wordclock Out.
The mixer does not work out of the box, but it shouldn't be too hard to get basic functionality, with a bit of hand-holding from Arnold.
Note that Focusrite in their infinite wisdom decided to re-use the model ID of the PRO 10 for the Liquid Saffire 56, which will make FFADO believe it's a PRO 10, try the bebop driver, and fail miserably. Until a workaround for this bogosity is developed, comment out the PRO 10 section in the file "configuration" in the FFADO source directory, add the following, and reinstall:
vendorid = 0x00130e;
modelid = 0x00000006;
vendorname = "Focusrite";
modelname = "Liquid Saffire 56";
driver = 20;
mixer = "Generic_Dice_EAP";
Put this snippet before the closing ");".
I'm currently testing with svn r1985.
With a non-rt kernel pre 2.6.39, the performance is not very good on my laptop. on 126.96.36.199 with threadirqs enabled, I can go down to 64x2 with only one xrun every 10 mins or so (still tuning to eliminate those...).