OK, the Two Big isn't for everyone, as you've most likely figured out by now. But if you're in need of a humongous external drive that performs as fast as an internal SATA drive, then this is the one for you. Sure, there are some limitations of what you can connect an eSATA drive to, but LaCie has already thought of this one and kindly bundles a PCI-X 133 eSATA card with the Two Big. This offers four eSATA ports and is backwards-compatible with 64- and 32-bit PCI slots.
The Two Big also comes supplied with a 2m eSATA cable, a power adaptor, two stands that clip on to the base of the case, and four rubber feet that can be stuck to the case.
One advantage that SATA shares with USB and Firewire is that you can add and remove drives without having to set the hard drives up in the motherboard's BIOS. This is handy if you want to use the Two Big to move large amounts of information from one location to another with minimal fuss.
As LaCie caters mainly for the Mac market - the G5 Power Macs have PCI-X slots ready for LaCie's eSATA card - it makes sense supplying a PCI-X card with the drive. However, for PC users PCI-X is usually only found only in servers or high-end workstations. If you really fancy a desktop board with PCI-X slots then Asus has the P5WDG2-WS which has two of them.
However, it would be much easier to get a motherboard with an eSATA connector already fitted too it, and there are several manufacturers that have offered this for some time now. The other advantage of using a built-in SATA controller is that most of them should offer speed advantages over the add-in card, at least on a PC. For Mac users the add-in card would be the way to go and it should offer much better speeds than the ones I achieved using a standard 32-bit 33MHz PCI slot.
I used the Asus A8R32-MVP Deluxe's on-board eSATA PCI Express controller to run some additional benchmarks to see if a faster interface made any actual difference. The good news is that it did, but not as much as I hoped for.