No, I don't think they are sub par. But I do think their exalted place in the Apple blog world is not earned by quality, but ad money. You don't see many of these bloggers actively using Squaresquare for anything but side projects, but they all push it as the go to platform to use even outside of ads. I would also contend that you can certainly buy your way in. See ads for stuff like Clean My Mac, which I am positive Gruber would never use himself.
I don't think there is anything extremely unscrupulous going on, just that there isn't much of a wall between editorial and advertisement with Gruber's model as some people claim.