Is a low output MC superior in sound quality to a high output MC??

Generally low output. Less windings on the core make the assembly lighter and more responsive.

Low output serves you more details, more headroom and generally a better musical flow. But to get the best out of it you need a Phonostage with higher gain. High gain and natural sound is a real task. And expensive.

Less windings mean less mass so low output MC's can give you a faster transient response allowing for more detail to be extracted. 

I have had both HOMC's and now an LOMC.  I won't go back to a HOMC again.  But as others have pointed out, the phono stage is critical.  It must be extremely quiet (no audible hiss) at the higher gain levels needed or you can negate the additional musical detail an LOMC brings you.

This low output MC mantra works only in theory, practically High Output MC can be very good or even better. I have tried both and i do not miss my new ZYX PREMIUM 4D with dedicated pre-pre amp, when i use vintage High Output ARGENT MC500HS cartridge.

I’m pretty sure it depends on the cartridge, if you chose between LOMC or HOMC of the same brand then maybe LOMC is better if your phono stage is good for LOMC, but you can find another HOMC cartridge (from another manufacturer) superior to your LOMC for example. It is very personal and system dependant.

I wouldn’t ignore HOMC or even MM in the battbe with LOMC cartridges.
But trust your ears!