My first impressions - most of the characters look and sound good! Even Jamie's Arthur. Joseph's voice over. I like a more maturer Merlin. The tension between Arthur / Merlin, Arthur / Morgan... \o/. Eva Green rocks as Morgan. Also, the scenery, WOW! The production value is high. My only problem might be Guinevere's voice (I mean the way she said "It's my duty..."). She looks the part though.
Trailer can be viewed at
http://insidetv.ew.com/2011/01/10/starz-camelot-trailer/