I think the new series is great =) Christopher Ecclestone is a great actor and although I wasn't sure if he was a good choice I think he really makes the show. There's been a lot of variety in the storylines so far and it's good fun telly xD I can't blame him for quitting after one series though, he is a famous actor and much in demand so it makes sense that he wouldn't want to get typecast (seen much of the other doctors lately? Little Britain doesn't count
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). Miss Piper is also a pretty good actress, I liked that Canterbury Tales thing she was in which was what got her this job too I believe. Better than the other Dr Who assistants that I can remember.
The special effects have seemed alright for me, only been a couple of occasions where I've notcied them being patchy (fire in first episode being a prime example). If there are any other huge sfx blunders then I'm just not noticing them because it's Doctor Who I guess
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Can't blame the beeb too much when they made Walking With Dinosaurs =)