Weather, either it be sun or rain, will wear the leather down quicker than if it were covered so it's just choice.
Do you want the weather to wear out your vinyl or your leather seat?
The leather can be conditioned to last a good long life in the elements so I wouldn't be afraid to get the leather corbin but you need to understand, it won't last forever. Some ways to preserve the leather would be to cover your seat in neets foot oil. Then, a nice finishing coat that will further waterproof, like a wax. If you go the route of the leather corbin, you should find a leather shop near you...like Tandy leather factory...and ask them what products would be best to preserve your investment. I use their products and they are excellent in quality.
