I watched (I think) episode 4, and it was just plain odd. I found the acting totally over the top, certain bits of the plot were obvious, and other bits came so far out of left field as to make no sense at all.
J.D, there was an explanantion about the genealogy, but I think it assumed I'd seen the first two episodes, becasue it went by at 5,000mph!
However, I was unimpressed, but I've heard rave reviews. Here's the Wiki bit on it:
http://en.wikipedia.org/wiki/Jekyll_%28TV_serial%29
Steven Moffatt also wrote 'Coupling', which was one of the funniest sitcoms ever, IMHO, at least until series three.