Is there a difference between brown and white champignons? My supermarket sells two varieties of champignons: Brown and white, with the brown ones being slightly more expensive.

Is there any notable difference between brown and white champignons in how they taste or the way you prepare or store them? Or is it rather like with brown and white chicken eggs where the differences are literally superficial?
Check this site: What’s the difference between cremini and white mushrooms?  

Brown(Baby Bella or Cremini) mushrooms have earthier flavor than the whites, you could use them based on your dishes' style or presentation.  

And the storing should be the same. Put them in some brown bag with normal temperature and do not freeze them. Slightly wipe the dust or dirt just before cooking, no need to wash by water.