The current issue of British Woodworking has an article by teacher John Lloyd discussing the merits or not of using magnetic guides, mine included. In Johns ambling manor I'm not sure exactly where he stands on the subject but I think he advocates learning the hard way, 10,000 hours practice was mentioned!
I remember when David Charlesworth first saw me demonstrating my dovetail guide at The West Dean College Show he bought five of them on the spot! Now that's a more enlightened attitude.
Any guide which helps make a process easier and more accurate without completely taking over has got to be a good thing, it also helps open the mind to other ways of working.
When I got to the end of the magazine I was surprised to see that the next issue features an article by John Lloyd on making a jig for planing mitres, Mmmm!