It all depends on your needs and equipment in your arsenal.
If you have lidar jammers i suggest mounting as high as possible. Visor clip if possible to MAX out your Radar Performence, although if your like me and just want to still receive every alert possible Midwindsheild is the place for you, as there you have the best of both worlds, and will pick up 85 percent of lidar shots and even 30 percent of the time on a high end unit scatter.
Now after personal testing i somewhat disagree with some other peoples findings on radar reception and mounting high high as in the Visor clip to some extent, I have seen miniscual gains in reception on Ka band. I am led to beleive this is do to the Narrowness of the "NEW" Ka band radars on the market today. It seems that when i mount midwindsheild I do get more range on Ka band Although on X and K band's mounting Higher increases range as the beam Divergences are alot wider than these newer 35.5 ghz ka radars.
I think part of this problem is due to maybe officer's improperly mounting radar antenna's towards the ground which I have now witnessed more than once. Next time you see your local Leo's check this out, and tell me your results.
My results have been.
Midwindsheild Advanced Laser Scatter warnings/ More warning time on Ka bands.
Visor Clip, typicaly gives better range on X, and K band Radar.
I have also found some, "NEWER" Cars such as the chevy colorado's have glass that is serated in nature i layers, which make it so that Laser/Lidar reception is Drastically Reduced to 1 percent, or Completely eliminated.
So be forewarned.
Fighting the good fight.
AlPiNe~