Yep... I have used the guide together with my own saws. The guide is 'fun'... it is easy to use... there are some limitations with narrower boards. The results (when the guide is applied correctly) are awesome. The DTs that I made using the guide were the finest I have ever made.
On the other hand, I confirm that the guide does nothing to improve small-motor skills. It does not improve freehand skills. I have cut a large ammount of DTs freehand, and the results get better every time... but are still of the quality 'made by hand'; still inferior to the DTs made with the guide.
I also noticed that the guide is best used with machine finished (planer / thicknesser) finished boards, as the results are intimately dependent on the board geometry; hand sawn / planed boards are less suitable. Peculiarly, the hand-sawn (eyeballed) dovetails work well with hand finished boards... something to encourage the purists.
Cut safe... ger