Curious, is it cheaper to use a reflector or TIR lens?
Using TIR lenses tend to make nicer beams, as in much less tint-shift, better-mixed light output, smoother hotspot, fewer artifacts, etc. as well as letting you “tune” the beam by using a wider-angle or narrower-angle lens, often interchangeably (not possible with reflectors except by “blurring” the hotspot by going OP or somesuch). All in all, I always seem to prefer the beams from TIR lenses.
I used to think that reflectors (Al) would be more expensive vs TIR lenses (plastic), but the predominance of reflectors has me wondering.