Big fan, I've watched nearly all of his LP's, some of them twice, as well as all of his collaborations with other LPers (which are probably his best work in my opinion.) He has mentioned being on the autism spectrum in his videos, although that surprises me because of how eloquent and sociable he is.
My one issue/complaint with his LPs is that he knows so much about the games he plays, and has been through them so many times that many of his LPs (the RPGs and less-action oriented, more strategy oriented games) come across as being too similar to video walkthroughs/strategy guides rather than let's-plays. Watching let's-players fail at a game to the point of frustration and react to new games as they are playing them for the first time is the best thing about Let's-plays in my opinion. That's why I love seeing Emile go through action games like Mario sunshine and galaxy and to empathize with his frustration and then elation when he finally succeeds, and Emile has a tendency to act hilarious when he is frustrated.