The Media Expansion Bar looks seamless from the front of the unit. It's very easy to plug in and get set up. For those of you who hate to read instructions, you should still be able to figure it out in a second. All the devices show up as a USB device with the specific type in parentheses/ () like so: USB Device (Compact Flash). This does make it quite easy to keep up with which card is which, just in case you wanted to make sure certain games were saved in certain places.
You can also use the Media Expansion Bar to copy files from one card to another. The only drawback is that as far as I've found, you'll have to copy them to the system first and then choose which card to copy back to, since the PS3 doesn't give you an option for where to copy, when you copy from a device. But once again, that's a PS3 limitation as far as I can tell!