I sold this to my wife with "it's written by the same bloke that did Blink and The Empty Child" (Stephen Moffat). That was enough, but the fact that it also has the man from Cold Feet (James Nesbitt) as Doctor Jackman/Jekyll was a bonus.
It is a perfect example of all that's good about British TV. Great acting, a willingness to take risks, 6 episodes of excitement and edginess with no filler. If it had been an American production for one of their big networks, it would have been at least 22 episodes long, all written by different teams of 5 writers, and 19 of those episodes would not have advanced the story one bit. They would have been very glossy though. The last episode of the "season" would have been forced to end on a cliffhanger to set up season two, which would then be cancelled.
Anyway, watch it if you get the chance. It kicks the arse off anything else on the telly and then eats their ears.