Rectify is very well made, but as mentioned, it's more a character study - how someone who spent all his adult life on death row - assimilates back into his community and how people react to him. As such, it's more like a play than a TV show.
Another Sundance offering is pretty interesting, albeit a bit convoluted - Honorable Woman. Again, very well acted and more action than Rectify. Definitely worth a watch if you like BBC productions and/or are interested in the Middle East. I thought it was far better than Tyrant.