I gouged my spray-in liner in a couple of places, usually when dragging heavy stuff across the bed, but they were surface-only gouges, never went all the way to metal. It's supposed to be easy to repair on minor gouges. Most body shops probably have a partial can of it in stock all the time and can make small patches in a very short time. Larger patches require cleaning to the metal and re-spraying the area.
Yes, it's slippery when wet, like most surfaces, but the textured surface helps with that. It's nowhere near as slippery as an unlined, painted metal bed when wet, though. And my brother's plastic drop-in liner is really slippery when wet, although that's a Ford and I don't know if it's the same composition as the FCA equivalents.