I think the only thing that drags it down is that if the PCs decide to go after all four cults, it could get repetitive. Otherwise, it’s a pretty solid sandbox campaign with one of the best intro adventures since T1 (I’m talking about the optional “Trouble in Red Larch” bit here).
I haven’t run PotA as a campaign, but I’ve used a good chunk of it to great effect in other campaigns – and I think that’s a real selling point of all the 5e adventure books.
Need a giant’s lair? Grab one from SKT. Need an urban sewer dungeon? Grab one from Dragon Heist. Need an elemental cultist lair? Take your pick from the ones in PotA. And so on.