Having seen the first nine of season one's ten episodes (I could go ahead and watch the season finale on demand, if I wanted, but I like to wait 'til broadcast night so I can watch it in glorious HD), I'd give it a 6.5 on a scale of ten. It's beautifully shot and pretty well-acted, but I've found the writing to be a bit flat, and, my biggest complaint, the lead character (e.g., Jonathan Rhys Meyers' Henry VIII) is the least interesting character in it (the most intriguing character is definitely Cardinal Wolsey, as portrayed by Sam Neill).
I'm not sure if the reason for that lies in the writing, or in the casting of Rhys Meyers.
Anyway, as a previous poster mentioned, it (sorta) fills the void left by the far superior Rome, not to mention Deadwood.
Fun fact: Did you know that Henry Cavill (Charles Brandon) was, along with Daniel Craig, in serious contention to take over the role of James Bond in Casino Royale, but was ultimately deemed too young?
Oh, and one more thing: my dad (who's already watched the final episode) told me that Peter O'Toole will be playing a part in season two. Cool.