GTE - I have thought about that for a while - cheaper to fly, maybe even a little more fun! But I quite like flying longer distances, and being able to fly IFR when required (which correct me if I am wrong but I don't think you can do in a microlight?).
Long distances yes, fun in spades - but not IFR I'm afraid.
On the other hand, any microlight should trim safely down to 45kts if you need to - which gets you nowhere very quickly, but is a lot more comfortable in marginal visibility than light aircraft speeds. Most will also land in cowfields and on beaches , and fly off them again, with minimal aggro. It's just another sort of flying really.
G