It looks as though the new PIX 240 Thunderbolt Caddy is really getting only a eSata speed since the SSD-original caddy is connecting to this new device through the eSatap port - which will bottleneck it at eSata speed. If one was to plug the new SSD directly into the new Thunderbolt dock, so you could get SSD speed directly out the Thunderbolt cable to the MacBook Pro, it would be extremely fast I would think. Maybe a re-design might be an idea.

See: PIX Dock | Sound Devices, LLC (http://www.sounddevices.com/products/pix-dock.htm)