Don't let them get you down. I have only used the covercraft brand but have been satisfied with them. Iam not sure which brands are available now since I bought mine new in '85. Like was mentioned before if you do use one I recommend only using it on long trips or at least removing it in the rain. They tend to hols in the mositure for days helping the rust cancer to the lower hood which is a common place to rust. Removing before or just after rains and using on long trips helped with my first z in that the clear coat was only on that portion in recent years. good luck and the car does look better without one and is a pain if you get under the hood frequently.
Enjoy the ride!
Enjoy the ride!