Kingy, Genghis,
I think that the cost advatage of microlight training over nppl grp A training will continue to favour the microlight for one reason - the cost of landing fees and the near impossiblity of even paying for circuits at some fields. Basically grp A needs licensed fields which cost a bit and charge !! micros don't need such costs and therefore are quite a bit cheaper. It really does make a difference.
(Admit that after you've got the licence a farmstrip can be cheaper but when you are down to say 12 hrs a year landing fees become relatively insignificant)
I fly both types and spend anything between £1k and £3k per yr dependant on how all the other things in life intervene.