I watch all the vlogs I can find, as a I keep a review/theories blog that requires pretty full ranging knowledge of the mythos.
I like MarbleHornets
Everyman Hybrid is alright, but it kind of jumped ship for me a while back
Tribetwelve is awful
I like the blog Brighter Than a Spoon because it's more of a story than a POV ARG. Most of the rest of the blogs get too self involved and become very hard to read.
For example I got sick of Just Another Fool and all the Core Theory Blogs. I don't have that kind of attention span.