dublinpilot, there's not much point in learning an inaccurate method when the correct MDR method is pretty straightforward, I would suggest.
I agree with IO540 about questioning the practical value of MDR and would certainly prefer that pre-flight computations were completed with a planned wind applied to track. Whether you use a whizz-wheel or elctronic device doesn't really matter, but I rail against current RAF methods of using high speed low level techniques for pre-flight planning in low speed aircraft flying at medium level - I've had quite a few ex-RAF basic students say that they've never been taught to use a Dalton computer; they use MDR for heading and 2 miles per minute for timing. Sorry - not accurate enough for a PPL Skill Test, chaps. But the RN and Army do still teach such things, I understand.
When I use a GPS, I do a quick MDR assessment of heading and groundspeed, so that I can fly the correct track without having to 'wind find' empirically when airborne; a quick look-see at the CDI bar will show how accurate my estimate was. But for basic beginners, I really do think that the old-fashioned whizz-wheel (or electronic equivalent) should be used and then heading and time flown once airborne. To start with. Then later on, once they've got the basics sorted out, by all means use GPS.
Some youngsters' mental arithmetic really is very weak indeed. But they must learn how to sort out an unplanned diversion and that is where MDR really helps. Draw line using edge of checklist and chinagraph, measure track and distance. If you've already worked out max drift prior to flight and drawn a wind arrow on the map, it's then pretty easy to 'do the maths' on the back of the checklist. Of course, if you know how to use a GPS, you can then enter the destination into the box and press the buttons - but if the diversion isn't in the database that becomes a bit of a faff!
I mean the 'generic' digital 'playstation generation' who can't think things out in their head, by the way IO540, not you individually.