Wish I could help, I am in the same position. I have been eying a couple units. I have been seriously looking at buying a used adat machine for a couple hundred bucks and running that into my layla 24/96 via optical input/adat and gaining another 8 channels super cheap.
It's just a thought. it's very cheap if you have the ability. A studio I use that used to use two adats does that using a motu interface and comes out with 24 channels digital with only the on motu interface. The layla only offers me an aditional 8 I believe but hey. 200 or 300 or 8 channels. What the hell.
Just so you know I am very happy with my Echo layla 24/96 but now days I have been looking at the presounus firestudio. I personaly don't have enough expieriance with fire wire to know if it's as fast as the pci interface of the layla. But the presonus has built in pre-amps and the layla does not.
Not alot of help I know.
F.S.