These settings will get you the best visuals for the cheapest cost. Turning the settings higher does not significantly improve the visual quality but it WILL significantly increase the performance cost. If you have a weaker GPU you may want to set things lower.
- Terrain scatter: off (assuming you have parallax)
- Reflection refresh: If you have Deferred or Textures Unlimited, set to Low. Otherwise Off.
- Reflection resolution: 256
- Antialiasing: off (use scatterer or TUFX antialiasing; stock AA is incompatible with HDR + Bloom anyway)
- Pixel light count: 8
In my experience, turning off temporal antialiasing and SMAA in scatterer and using temporal antialiasing in TUFX gives the best results. If you're seeing blurring or smearing when the camera or objects are in motion, it's almost certainly because of some combination of these options. Try turning all of them off and then re-enable one at a time.