They are awesome for road trips or for the track where your paint is going to be bombarded by rocks and bugs. They are NOT for daily driving though. I only use a bra on my car for road trips. I don't have one for the Legacy since I don't take it on long road trips, but I would if I did. People who leave them on all the time are the ones who find that they damage the paint.
So let me see... someone left the bra on the car 24/7 through wind and rain and snow and for some reason dirt and sticks and leaves got underneath it and scratched and stained your paint? Wha...? Surely you jest.

Damage like that is to be expected if you neglect something that is only intended to be used occasionaly. They are a great product to protect your paint, but only if you get a quality bra (like Colgan Custom) and you keep it clean. Tempoary use is best, but if you are going to leave it on all the time then just make sure you take it off when you wash the car and do your best to keep it clean.