My cousin Scott wrote three very excellent posts on his blog about the Top 30 TV Shows of the Decade. You should go check it out, then come back and keep reading. Don't worry, I'll wait.
Oh, you're back.
I was talking with him about shows that I like, and The Man in the High Castle came up. He was about 3 episodes into season 1 at the time, and I was about 5. I told him it was slow to start but he should stick with it. For me the show was beginning to pick up. I had no idea just how awesome it was going to get in the remaining few episodes of the season.
The show is like that unsuspecting old-person, who's sitting across from you, playing cards, when suddenly he stands up and punches you in the face. Strangely, you don't seem to mind the sudden fist-a-cuffs.
I don't often recommend a television show--at least not here, but The Man in the High Castle should be watched and hopefully enjoyed. It's very different from the book, although the character of Frank Frink is just as useless as his literary counterpart--if not more so. Frink was sort of the defacto main character of the novel and his story fell short. His scenes in the show might be the reason the first few episodes run so slow. Once the focus turned to Juliana, things begin to pick up. Her character is also better developed in the show. She's no longer merely a set-piece, but plays a very strong role in the plot.
I don't dislike the book, but in this instance the show is a lot better than the original source material. I have similar feelings on the Lord of the Rings.
I'm looking forward to Season 2, and hope that it keeps up the momentum. It's a very good show and has the potential to go in many different directions, or dimensions.