Since someone mentioned The Adventure Zone, I will say that though I haven't listened to it yet I have one friend (who I unfortunately haven't been able to play with in a game yet) who loves The Adventure Zone and dislikes Critical Role, so there's different flavors of actual play shows that appeal to different people.
For whatever reason, though, Critical Role is the only one that has gotten an officially published book from WotC, a comic series from Dark Horse, and an upcoming two season animated adaptation on Amazon Prime. Probably has a lot to do with the fact that the players are almost all voice actors with a decade or more of industry experience and high profile roles (the video game Saints Row: Gat Out of Hell, which released before Mercer's campaign became the Critical Role livestream, actually has one of the game's voice actors/future star of Critical Role making a reference to the campaign's animal companion Trinket the Bear).