The USBCard costs the same as Corsair's Flash Voyager, and has the same 4GB capacity. Its credit card design means you can slip it into your wallet and carry your data with the rest of your valuables. A slender connector folds out from the card, so there's no cap to lose.
Freecom's USBCard managed respectable read speeds, but was very slow in our write tests. Despite this, its low price and convenient shape make it a good choice for occasional use.