Any switchmode device generates loads of splat which even a good LDO can't clean up completely. The main reason is the very fast high current switching spikes coupled with the unavoidable inductances of PCB tracks and all components.
If worried about super clean dc, avoid.
Only where good efficiency and eg long battery life are important is it worth doing, and even then it may not work adequately - I tried this when designing mobile phones years ago and eventually gave up and stuck to linear.
Mind you, I needed < 1uV noise levels, so this may not be relevant in your application.
Allan