I have just returned from a month shooting in Namibia using a Nexto CF. All I can say is that this device is truely excellent - highly recommended.
I bought the 100GB version with extended battery for GBP220. I charged it up before I left, and copied my CF cards over to it every day at the end of shooting. It is extremely fast, copying a 2GB card in about 3 mins. The battery is also very long lasting. By the end of the trip I had copied 65GB without recharging, and the battery life indicator had just dropped to 1/3rd. You could probably get over 80GB on a single charge in real life conditions.
The only disadvantage is it doesn't take AAs, but with battery life like this, who needs AAs?