Every Oban visitor should eat at the Seafood Shack/Hut on the ferry terminal pier at least once. The best value-for-money seafood you can find anywhere and I have lived/worked in over 50 countries during my 50 years of working life.
The lobster is the best I have ever eaten. The staff are lovely too! We did not stop eating various seafood until we could just eat no more! Brilliant!