my moto x 2014 got 5.1 update 2 days ago,and its just awsome.
antutu after update-47203,damn good for sd801 with 2gb ram,beating every sd801 device out there by 2-3k,LG G3 by massive 10k.
i think moto x series is their main focus when it comes to update,coz on paper moto turbo is their offical flagship,but they focus more on moto x series followed by moto G series.
just an observation,although i might me completly wrong
regarding moto x 2013,i think people should thank moto for giving support to 2.5 yr old device,even though the chipset dont support os anymore.they are still working hard to provide updates as long as possible.
if things goes well moto x 2014 will be alive for atleast 2 more yrs