I have one of Joseph's boxes (an RS232 version) - dont like usb and avoid it whenever possible, lets be honest what 'seems' more reliable a connector that pulls out if you breath anywhere near it (USB) or has big locking screws holding it onto the computer (RS232) - I know which route id choose. As an added bonus - as more of my gear gets ported over to the PICs its soooooooo much easier to use RS232, and even my little PIC12F629s can control RS232 equipment.
I would highly recommend the dusky controls box for controlling your sky box.