Re,- I think we perhaps expect more from them than their design allows.
Quite true Dave, - not sure what the Dremel is, (125w?) but mine are similar and only 135w (not much more than a big light bulb) so not really for leaning on, (rely on revs not torque to get things done) If it's your switch that's dud, and if this is the switch, buy a sack full for spares.
220v 5 speed just not linear. Cheap enough to just buy one to try.