[Chimpakt]

It really depends on your team. Certain pokemon can utilize stealth rock support better because most of their switch ins are levitating. Obviously a pokemon like donphan would appreciate stealth rock more than something like Hydreigon.

But spikes is not widely distributed and only certain pokemon will be able to use it effectively. Stealth rock on the other hand can be used by a variety of pokemon and it effectively ALWAYS deals damage so it is generally better.