I had them on my van 20 years ago as they were on it when I purchased it. It used to leak water and the headlining got damaged because of the water leak. So my opinion is that they look cleaner without them. There is always a potential for rust to develop also.

When I resprayed my van they came off.

However as they are already there when you bought the van, its not as if your drilling any new holes, plus it will be less work for the panel beater, thus reducing costs.

There you go, a bet each way.

Geoff