I have to say looking at the jigs you have linked to, I am surprised anyone would want to spend 50 quid on a piece of kit you could nock up in your shop for under a fiver (including a dedicated clamp)
Am I missing something or are we all getting too reliant on expensive pieces of tat, where do you think the Pocket hole jig came from, sure in wood they wear out from time to time but for another 60p you can soon rectify that.