I just run everything as application/performance in the driver. On a laptop (i7-3630Quad, NV GTX-670MX, older ASUS OEM drivers) so have lower detail settings and such set in game to keep the FPS nearly locked at 60, so the transition is very slight and barely noticeable.

Even if I had the extra horsepower, I would probably still keep the detail settings low because it just looks too unnatural for things to be so sharp all the time. Especially shadows---shadows from trees and such shouldn't have so much definition anyway, especially if the wind is blowing through them. I also don't like some of the banding that shows up sometimes with filtering either (AF/Tri/Bi)--not to mention the shimmering effect that can crop up during movement. Sometimes the highest settings cause more annoyances than just the performance impact. I prefer to have more consistent frame rates.