Definitely The Smiler for me.
Actually has a decent ride length which is rare in the UK and despite the concrete pit, there is loads to see as you get up close and personal with the coaster which I actually find entertaining.
I have never found The Smiler rough and controversially I have never found an hour listening to the music irritating.
So overall, good ride length, intimidating theme, intimidating music, 1 good and 1 great pop of airtime, record breaking inversions which I do not find repetitive. What's not to like?
Though a distant second to Nemesis in my book, it's still a great thrill coaster and my UK number 2.
I find Saw very pedestrian.