Both are based on very reliable SirfStarIII GPS technology. If you have BT built in to your laptop or are considering a BT dongle, The BT-368 would allow flexibility of placement away from the laptop. The BU-353 is a USB GPS and must be connected to the laptop. This limits placement options but this GPS would not require charging. The BU-353 is a great GPS and I would bet the BT-368 is just as good.
I prefer the BT option but have not used that particular unit.