As I spend more time with the display I am also going back and forth on what motion setting to use.
For the longest time when watching 1080p/24 content via blu-ray I ran with Cinema Smooth set to On. But I started seeing some issues. Flicker mostly. The picture just seemed unstable.
So next I turned Cinema Smooth and the other motion setting to off. This certainly stabilized the picture quite a bit but had it's own issues. More judder for one. I experimented with the TV accepting a 24p signal or having my blu-ray player do the 60hz pulldown but both seemed similar. But it's worth trying both depending on what blu-ray player you own (Mine is the Sony in my signature). Cinema Smooth off also changed my grayscale calibration quite a bit compared to it being on.
Now I'm rolling with Cinema Smooth off and Motion smoothing set to Standard. And the clarity is incredible! You see much more detail in the image. But the picture IS a bit too smooth at times. My other display devices are from Sony and I've decided that I just like how they handle motion better than the other brands. My Sony LCD has less visible SOE with the lowest smoothing setting....as does my Sony projector. But both get the benefit of the increased motion resolution with less downside than the Samsung IMO.
Living room: Sony 60NX720, Yamaha RX-V673, NHT Super One/Zero w/Ten Sub, Panasonic BDT230.
Current Man Cave: Samsung PN51F8500, Vizio S4251w-B4, Sony BDP-S5100, Darbee Darblet.
Future Man Cave: Sony VPL-HW40ES, Monoprice 106" Multi-Format Fixed Frame (Never again!).
Displays calibrated with HCFR, i1DisplayPro, and Colormunki Photo.