FlyingKiwi_73,
Whilst the above remarks about polarised sunglasses are correct with regards to LCD screens, I think this thread so far smells a little negative!
You only gave GPS as an example - in that case, GO FOR POLARISED! If you are flying an aircraft equipped with analogue instruments, but with a portable GPS, you won't have a problem. Most portable units in GA are not any more difficult to see with polarised glasses than they are with standard sets. This is because the majority of them are not of a particularly high 'pixelage', and a bit ancient in technology. If you DO have a more modern LCD screen GPS, do not fear - polarisation only affects viewability in certain planes of vision. For example, if you look at the screen and see is as completely black, for example, just swivel the GPS unit a little until you can see it clearly.
I will echo above comments with regards to glass cockpits - yes, it is a BIG nono and would be especially dangerous if you were flying IMC relying on all the data from those screens.
There are a multitude of benefits, least of which are things like being able to look pretty much anywhere in the sky without having to squint at all, being able to see twice as far in haze as a 'non-polarised pilot' etc. I don't know how to describe it exactly, only that I honestly feel I would not enjoy my private flying half as much if I turned up at the airfield having forgotten my polarised prescriptions!
Safe flying
