Is all name brand oil that meets specs the same?

In some cases the upper product levels don't exist though.

Mobil Super would be the equivalent to Kirkland or Supertech, then there are three tiers of product above that though, which don't exist in those competing brands.
Just so we're on the same page, what are the three higher tiers, maybe with examples?
What defines the difference between EP & AP? Where does ESP fall in this hierarchy? Thanks ... very interested in your thoughts on this.

ESP is a whole separate thing because it focuses on emissions systems protection, which is driven by specific approvals. The same goes with M1 0w-40, even though it falls within the "Mobil 1" tier of products, the approvals it has sets it above things like the mileage limit for that tier. These products don't overlap with the regular M1 oils and don't compare (because of the approvals) to the SN/SP Energy Conserving oils we are mostly discussing.

The difference between EP and AP is that AP was designed for even longer drain intervals, which means an even stouter additive package. We also saw more PAO in the base oil blend in many of the products over EP, which has more PAO than plane-Jane M1.
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Regarding the OPs question and OCI drain intervals, technically yes, these oils do vary in additive pack etc. Practically though for a normal passenger car, used normally, I’d wager as long as the oil in question meets the approvals required and is in the correct grade I doubt you’ll see much of a difference one way or the other and that car will go to the junkyard with a running engine and if not, the oil brand will have no consequence as to why the engine failed.

That being said I do run Mobil 1 euro in my truck because it reduced start up noise albeit I’d guess that’s more a function of viscosity change. I highly doubt it makes any actual difference whatsoever over the length of ownership though just fun stuff to do.
Just buy M1 on sale and then the differential is nowhere near as large. I change via the OLM, so I'm running the same interval regardless. Short changes are a waste of resources, though I understand many won't share that opinion.
I have a real world test of that. I service 3 Acura TSXs. We bought our 2006 TSX new in Dec 2006. I have serviced it at 4K to 5K intervals with mostly M1 since new. 205K on the clock and doesn't burn a drop. My sister drove our car and went home to Gig Harbor, WA and bought a 2007 which is the same car. Dealer and quickie lube serviced by the OLM. Car now has 100K and goes through 1/2 to 1 quart between 5K services (I have her car and gave it to a friend). The 3rd, another 2007, is a friends we got at the local MBZ dealership maybe 2 years ago. Dealer serviced by the OLM based on Carfax history. It has about 140K on the clock and also goes through a little oil between services.
I believe the drivetrain in our car is better than the other 2 cars. Was it the oil or the service schedule? Probably both.

Now I understand this is just 1 test scenario, but it's a good one and I find it interesting. If you are keeping a car for, say 100K, perhaps the OLM schedule is fine. Personally I am sold on 5K services regardless. That's my story and I'm sticking to it!
Is name brand oil, (castrol, valvoline, pennzoil,...) that meets required specs, (dexos..) basically going to give the same results for basic passenger car driving, within a category (synthetic, synthetic blend and conventional),? I was going to ask if they were the same but I know every manufacture has an additive here or there that is proprietary so I just stuck with the idea of, gives the same results. I went to walmart and had pennzoil, castrol, and valvoline in my hand and was wondering if it makes any difference to pick one or the other. I change conventional at 3,000 and synthetic at 5,000 and unless told otherwise think major label oil will all work just as well.
I like Valvoline Advanced because it smells good, has a good add pack, doesn't have settled deposits in the cool pouring jugs and the machines run quiet on it. 😄