I was just at Walmart and ran into a killer deal. 5L jugs of Esso Extra 5w-30 for $7.99Cdn limit 2 per customer. Regular price $14 per jug. I bought two and I think I am going to buy another 2 tomorrow. Is this as good as a Petro-Can oil or Castrol GTX 5w-30?? Should I be stocking up on this stuff??