Kingy, we all have our personal biases about what's best to fly - but so far as I can see, servicing, hangerage, permit fees and fuel are pretty much the same on cheaper microlights and cheaper PFA types. How costs then pan out is largely down to useage.
Without doubt the most expensive group A are more expensive than the most expensive microlights - stands to reason since you can hang more toys on them that have running costs attached. But down in the weeds, I don't think there's anything in it - the only real difference is paperwork. Initial training and outright purchase costs are less for a microlight, but the NPPL has largely now made a nonsense of the former, and syndicates can trivialise the latter for anybody on a very low budget.
Genghis
Who flies both microlights and group A, often from farmstrips.