I'm a big Phillip K. Dick fan (AKA Dickhead)
I've read all his major novels, and I have to say that out of all his works "The Man in The High Castle" is my least favorite. Maybe least favorite is unfair, how about most frustrating. It pulls you in, gets you thinking critically and deeply about the very nature of ourselves and even our reality and then, just as it starts to feel like it's ramping up to a great climax all of a sudden... ... wait, what... that was the last page... seriously... it ends just like that...

I wouldn't expect a TV series to be 100% true to the novel (they never are). But I can see how the world that Dick created could be a fantastic setting for a dramatic series or movie, (It certainly worked for Bladerunner and Minority Report) I don't watch much TV but perhaps I'll check it out.
P.S. I'm really surprised that nobody has done a movie or series based off "The Penultimate Truth" yet also.