I had alloy gators on my 350z when I bought the car. I removed them because they looked lame and I wanted the wheels restored. When I removed them I found that they'd caused a lot of corrosion due to the build up of crud behind them.
Maybe they hadn't been installed correctly, or they were already in a bad way.
This would be my concern.
If you can't clean behind the protector corrosion might mess up your wheels anyway.
Thus far I've managed to keep my wheels immaculate.
I think rim protector tyres are the best option, with some spare cash in the bank for a repair if required.
My partner has steel wheels on her car and I will buy steel wheels for her next car.
A new set of plastic hub caps is cheaper than Alloy Wheel Repair.