I think of Macaskill as doing tricks/stunts rather than riding, and Akrigg as riding with trials stuff thrown in, if that makes sense? Like Akrigg does stuff that’s hard and very creative but maybe not super-showy, that Macaskill might not be interested in if he could be doing a massive drop off a castle wall instead.
That’s not to knock Macaskill, and as unklehomered suggests it might be as much to do with their different approaches to making and putting out videos as anything else, and obviously Macaskill can do other stuff too.
So while they’re both awesome, if we’re just going on their vids Akrigg edges it for me. I like it that he does the editing/production too.