Primary criteria: Writing quality. Does it make sense? How is the spelling and grammar? Is the writer clear in their concept?
Are they just trying to sell me something? And if they are selling something, are they giving me valid reasoning and common sense?
I have hopped a lot of hubs, and if the writer cannot spell or use appropriate grammar it detracts and distracts the reader. So I stop right there. If there is only a hateful rant, I stop. Sometimes the english language is so badly abused that the article is pure unadulterated nonsense and I stop. When I stop I vote down. I have even gone so far on one or two occasions to flag a hub if it is too bad. But I don't like doing that.
I once read a hub that had a valid point, but the writer used a lot of vulgarities trying to get that point across. I sent him an email suggesting that more people might listen if he were to not do that. I did not vote either up or down, and I did not yell at him in a comment. I just made a private observation. He read what I wrote and made his own editorial changes.