Season 1 did not really convince me, but a year and a half after I saw it, I still got myself season 2.
Well, season 2 is not really much better than I remember number 1, but I would not rate it 1,5 stars. Season 2 is more historical and less based on myths and sagas. It mostly tells the story of Lothbrok raising in power, travelling to England and making friends and enemies. Story-wise season 2 is more of a soap opera with more focus on the relations between people.
I still cannot say that I really like the series. I still might some day watch the third series, but they did not come high up my list after watching the first two.