Carpet or cladding for walls?

I’m looking into getting a van converted and wondered what the pros/cons are of carpeted walls vs wooden cladding?
Does the carpet get damp, go mouldy, smelly? Is it easy to clean? I’m told the one the converter uses is moisture proofed so this shouldn’t be a problem but first hand experiences would be appreciated.
Likewise with wooden cladding - does it absorb moisture and thus become warped? Does it end up ‘popping’ out of place due to the rough rides on our UK roads? Is it harder to maintain due to needing painting/oiling/varnishing regularly?
What are people’s experiences with the different types of wall covering, any gotchas I should be aware of?
Thanks in anticipation