Short answer: if you are paying retail and still changing your oil every 3,000 to 5,000 miles regardless of what the data sheet allows, no, you are paying a premium for protection you are throwing away early. If you are running the actual recommended drain interval and buying at wholesale, the math works in AMSOIL’s favor on protection per dollar, not just price per quart.
I have run AMSOIL through 20 years of off road builds, a Road King, and a daily driven Camaro through Texas summers, conditions that punish oil. The lab numbers back up what I have watched happen in the field. Signature Series carries a TBN of 12.5 against the 8.6 to 10.1 you will find in Mobil 1 and most other synthetics, roughly 35 percent more acid neutralizing reserve left at the same mileage, which is why AMSOIL can support drain intervals up to 25,000 miles instead of 5,000 to 10,000.
In TEOST 33C deposit testing, AMSOIL measured 3.6 times fewer turbo deposits than the industry average. If you are running a turbo or a high output engine, that is not a marketing line, that is the difference between a clean turbo at 100,000 miles and a sludged one.
How does it actually stack up against what is on the parts store shelf? I have broken down AMSOIL against Mobil 1 head to head with the lab numbers, not the bottle claims. Castrol and the other major synthetics land closer to Mobil 1 on TBN and NOACK volatility than they do to AMSOIL, so the comparison holds in the same direction either way.
Worth it for daily commuting in a new car still under factory warranty intervals? Probably overkill. Worth it if you are towing, driving off road, running high mileage, or just tired of oil changes every three months? In 20 years of selling and running it myself, yes. Call me, tell me what you drive, and I will tell you straight whether it is worth it for your specific situation.