Frankly, I'm surprised by the number of negative reviews of Painkiller Jane. It seems to me a competent, if not exceptional, sci-fi series with considerable entertainment value, interesting characters, and sometimes engaging plot lines. Some episodes are derivative but none are truly bad, except perhaps for the pointless clip show in episode 16.
It certainly focuses more on the emotional than the cerebral, but that's not really a criteria for judging a show, not even a sci-fi show.
The writing is solid and the main characters are competent actors. Kristiana Lokken is definitely more than just eye candy -- although the eye candy part does add to the watch-ability -- and she creates a sympathetic and occasionally complex character. (She is credited as a co-executive producer of the series, whatever that means in Hollywoodese). The other main characters are equally competent, although some of the supporting actors are 2nd tier.
It is a bit loose at times but it starts to tighten up toward the end of the season when the focus shifts toward following a story arc rather than the neuro of the week, episodic format.
I suspect many of the negative reviews arise from two things. The first would be viewers who might be comparing it to the comic book, which I have not read, and which should be irrelevant. The second would be production values which are generally based on budgets. There are no mind-blowing special effects in Painkiller Jane, nor should there be. It's not a space opera.
Overall, I think this show got a bad rap, and I would definitely recommend it to sci-fi fans for it's entertainment value.