I have watched all, bar the current season (6). The season set in Belfast has to be seen to be believed. The Oirish accents make Tom Cruise's efforts look *************************.
That one guy playing the IRA leader, I think he's actually English, has the worst Irish accent I've ever heard.
The first 2 series were very good but it's rubbish in the last series. The only thing that kept me watching was the cute doctor.