Hardware :: FireWire 800 Daisy - Chain Vs USB 2 - Which More Efficient?

I'm running two of these enclosures: [URL] each with 2x2TB drives in RAID0 (i.e. 4TB per enclosure). I use one 4TB array for my user files, and the other for TimeMachine. My user array is connected via FW800, my question is - is it more efficient to connect the other (TM) array via USB2 or via daisy chained FW800? The enclosures use the Oxford 934DSb chipset, which is capable of saturating the FW bus, so thats 100MBps. As i understand it very few interfaces are capable of saturating a USB2 bus such that practically speaking even FW400 gives greater real-world throughput than USB2, despite the 60Mbps difference in spec.

Since one is a TM volume, when backing up from the user array to the TM array will the data have to pass through the computer's controller? It definitely will if it's FW800 -> USB2, but will it have to if it's daisy chained FW800? I'm told this might not be the case as some FW controllers support P2P communication but i can't find too much info about it. Even if there is P2P support the OS needs to know the progress of file transfers and so forth so can it do this even if the drives are transferring via P2P or can it only monitor that sort of thing if the data goes through it's controller? Essentially is it up to the OS or the controller to select the optimal route for data? If it's up to the OS does Mac OS support FW P2P? That said, even if the data does have to go to the computer from one array and back through the daisy chain to the other array, is it still practically faster than the USB2 route?