I don't know what is "best" and never will, but have experienced zero difficulties with wear or corrosion via the simple stuff done for a very long time.
Top priority, never put one away wet or even damp and store in a dry environment - attend to them on a schedule using what has worked so far (RemLube or Hoppe's here - sometimes ATF based mix). Clean the bores soon after shooting - the cleaner is some one-off stuff in smallish plastic bottles a knowledgeable guy sold or gave me a long time ago at a local gun show - still on the market I think.
For stubborn powder residue/dirt, using Kroil.
Good thread - thanks - responses as diverse and opinionated as some predicted.
