Just finished Season 3 Episodes 3. I am greatly enjoying it, but I won't post any spoilers.... yet.
Hell yes! Since I was born in the 80's in the USSR, this third season is like reliving parts of my childhood that I've forgotten. I really enjoy the fact that they decided to expand in this third season and now the whole upside down world ain't just your "something that may have happened on your backyard in the little midwestern city of US", but now it's more like "oh fuck, just great, shit!". Netflix really decided to step with this one.
Thus far S3 -> S1 -> S2 as far as I'm concerned.