The 300 mmm one looks to be the same as they have sold for years in different incarnations. Mine dates from when they were branded "Perform" and painted yellow. Haven't used it for ages as I prefer to do it by hand these days, but it still has it's place and if I had a long run of dovetails to do I'd probably drag it out and use it.
They work pretty well but set up can be tricky and must be done very carefully to get good consistant results, you'll find this nigh on impossible if your router does not have a good fine adjuster. A few thou out on the depth of cut will make the world of difference to the fit. You also need to take into account that spacings can't be altered - 1/2" tails and pins are what you get (though I think there is a fine template available for 1/4") - and I found best results were obtained by tailoring the size of the box/drawer sides to match these dimensions which is not always practical.
One tip regarding depth of cut:
I found on mine that the perfect setup required a depth that meant the bearing on the cutter was only just in contact with the template. A good fix for this is a 3mm hardboard spacer below the template (cut through the hardboard as well on the first run so the fingers are supported) - you then get much better contact between bearing and template, and has the added advantage that the cutter is further from the fingers of the template reducing the risk of costly damage should you have a little slip.
Does make good strong joints though, once you've got the hang of setting up and using it.