Defiance is now free to play on PC, and from 15th July should also be free to play on 360 and PS3.
I quite enjoyed it but didn't spend a huge amount of time playing the game. I also thought the TV show was utter pish, although I only watched a few episodes.
The free to play decision, which seems like an admission of defeat to some extent, coincides with the start of the second season of the TV series.