I have been using Serengeti's for the past 4 years in a full glass cockpit. I prefer the Drivers lens. I have tried the Drivers Gradient, which washes out the darkness from top to bottom, but find that they don't take away enough glare.
The only possible problem with Serengeti's, is that the back of the lens is coated in a material that reflects your eyes if the sun shines directly on you. It is not a big problem though.
Really excellent glasses. Much better than the Raybans I used before.