Which mk3/mk3s filament sensor performs the best the mk3s ir sensor vs mk3 laser sensor?  

RE: Which mk3/mk3s filament sensor performs the best the mk3s ir sensor vs mk3 laser sensor?

The MK3 had real problems with transparent filaments.

The Mk3S design was intended to correct that - and it does. It works with all filaments.

It is also quite touchy to get working correctly. Mine required a little spacer. Very reliable now.

RE: Which mk3/mk3s filament sensor performs the best the mk3s ir sensor vs mk3 laser sensor?

Both use the same underlying code.  The MK3S is a mechanical switch (IR based, but senses a mechanical difference); and the MK3 is optical, sensing motion.  

The mechanical sensor design is Rube-Goldberg.  Magnets holding magnets in close proximity to a motor with stronger magnets.  Plus a few rough moving parts using a screw with sharp threads as an axle.  And the parts are printed, with random sizes based on printer calibration or lack there-of, and dimensional unstable. 

The optical sensor is a grand idea, designed to sense motion of moving metal in conveyor applications.  But the key here is it wants a solid object that is metalic and reflective to the laser light it uses.  Plastics tend to not be reflective, and tend to absorb the light used.  Translucent and lighter colors being the worst, and for whatever reason the optical sensor doesn't see them moving. 

Both sensors depend on the firmware. The firmware has been known to be very flaky around the sensors. Both of them. A filament-out can come back as an indicated Power Fail, recovery from a filament out condition can end in endless loops, a hang, or sometimes it works as expected.  Again: this feature is found in both sensors.  And, after power-out the printer has been known to tell users filament is out, even though the filament spool is full and the filament is loaded.   And, in both interrupt driven events, it isn't uncommon for the feature to simply lock up when they occur. 

Best option?  Watch the level in the filament spool and handle it manually: do not trust the filament sensor; and keep the sensor disabled to prevent anomalous bugs from bothering you.