wulimaster, the Ford WSS-M2C153-H spec for 5w-20 also requires that at a minimum any oil must meet specs for API SL or SJ and also pass a double length Sequence IIIE or IIIF test with a limit of 200% viscosity increase. The limit for the SJ Sequence IIIE test was 375% at 64 hours and for the Sequence IIIF 275% at 80 hours for SL. The old sequence IIIE test uses leaded fuel and as such even though it is a shorter length is comparable to the newer version of the test when it had the viscosity increase limit of 200% to meet Fords requirements. Also the limit for the TEOST is much lower than either API SJ or SL. The TEOST test measures doposits left inside the engine. These changes make a Ford spec 5w-20 oil much more robust than the average API SL motor oil that does not meet the ford spec. There are also requirements of GF-3 and GF-2 such as limits for phosphorus content. API SL and SJ also have other requirements that I have not listed.
In my opinion the API specs for SL and SJ motor oil are not hard to meet and if you want better protection for your motor and don't own a car that specs 5w-20 then only buy an oil that meets the European ACEA specs of A5 and B5 or A3 and B3 for a vehicle that requires a higher viscosity motor oil. These ACEA specs are far harder to meet and would give much better protection than most oil meeting only the SL or SJ requirements.