Devices like the OCZ Z-drive which go into the pci-e slots are essentially tuned hardware raid controllers with SSD's attached. The manufacturers use the pci-e slot. (in the case of the Z-drive it's a 8x slot) to overcome the 3 Gb/s limit with the SATA interface. 3 Gb/s is about 300 MB/s where the z Drive does somwhere around 500+ MB/s of data throughput.
My question is, are there any configuration issues inherent with using PCIe SSD's as boot drives and is there anything to be gained by doing this? I have a friend that reads catalogs and then throws these types of configurations at me and honestly I don't see any gains.