I heard him playing with a dancer in Edinburgh (an actor called "Tap Eire") about three years ago, doing a sort of knowingly self-referential Irish trad. He was excellent and I'd go to hear him again.

No idea what Ashley Hutchings does; I believe he led some over-arranged English folk-rock band in the 70s. Not a genre I care about. I presume any performer from that era will have done as many drugs as MacIsaac. It doesn't matter either way.

: Buddy MacMaster seen playing with him on YouTube is widely regarded as
: the greatest living Scottish style fiddler.

Maybe he is so regarded in Canada. There is no unique Scottish style, and there are many other players who can do the other ones better.