The MemPlug is very well machined and feels very sturdy. The MemPlug that I received is made of a sturdy smokey grey plastic. It has thumb ridges that make removing it very easy. It does stick out of the back of the Visor (rather than being completely flush) a little more than a millimeter, but you don't notice it at all. 

I've always been a fan of CompactFlash over SmartMedia. I'm starting to realize though, that it's a VHS versus BetaMax situation. CompactFlash is used everywhere, PocketPCs, Cameras, Laptops with Adapters, it's ubiquitous. SmartMedia is less common. 

Some cameras use SmartMedia with much success, but it's not a format that you see everywhere. However, the more I use SmartMedia the more I prefer it. It's a tiny and incredibly thin wafer, thinner than a credit card. When inserted into the MemPlug a SmartMedia card sticks out just a tiny bit. This is almost necessary, otherwise you wouldn't have enough of the card visible to grasp with your fingers to remove it. I'd still prefer, for my own comfort, if there was a way to have the SmartMedia card exist entirely within the Springboard Module. 

When you compare the MemPlug SmartMedia Springboard to a CF Solution like the MatchBookDrive or InnoPocket, you notice that there's a lot more circuitry in the MemPlug. The MemPlug includes Flash Memory with the Palm Software. They say this internal memory can also be updated with future software updates. 

One other significant feature that makes SmartMedia appropriate for Visor's is it's low power consumption. Most CF Cards draw about ~30mA, while SmartMedia cards sip power at less than <0.02mA. I didn't drawn my Prisms battery at all even after a full system Backup to a SmartMedia card.