[Savage GT]

I prefer cars to have them.
Generally they are a snug fit, but if the inserts are prone to coming off a smearing of uhu in the appropriate places keeps them in place.
I also like the one piece styled alloy wheels, but sometimes you can not get those in the size/style or air versions you want.
I don't like no inserts on standard wheels personally.
In all my time in this hobby, i have never managed to acquire a dent in a wheel.
In the question of inserts preventing dents, possibly the older ones that fit to the wall of the wheel might help, but I prefer the ones that slip over the axle sleeve myself.
My only gripe is usually with the likes of Sideways cars where they are so tight from the factory an attempted removal risks damaging the insert.