From Duncan about 6 months ago.
Not sure if you are hitting resolution problems or not. The bumpBlur should help a lot at the horizon, although if you have a lot of triangles it can't help with the displacement occlusion detail. If increasing your antialiasing levels doesn't work, then you might try going to 4K renders then resizing back down to 2K using a resize utility that filters the resize( most do ). This is brute force antialiasing, but can help with Maya sometimes. Maya does a 2 volley antialiasing where it first does test sample sin a pixel then if this is over a threshold it does a second round. A more hierarchical approach can create smoother results, but rendering at a larger resolution and resizing down sort of provides this. You might also try using mental ray.
Duncan