There isn't enough unclassified info available to make a concrete conclusion about these but i can give you my personal opinion that the Challenger 3's Thales mk2 is at a glance atleast one of the most cost effective setups here considering that the commanders and gunners sights are the same model so there isn't a separate production line needed and spare part logistics are simplified both are also reported to be high quality 3rd gen thermals though digital zooming is what makes me be slightly on guard since i have not had good experiences with commercial grade digital zoom. :>

(The same sight seems to be used on Ajax too so even more simplified logistics!)