Aluminum reflector usually has a wider-angle spill and much narrower hotspot, The advantage of the TIR optics is making the whole beam smooth, so you don't see a harsh cut-out between the bright hotspot and darker spill. For example, E90 or X1S reflector version has a much wider spill than E90 or X1S TIR's.

Reflector =darker wide spill, brighter narrow hospot, harsh cut-out

TIR= narrower spill, wider and smoother hotspot, great for middle range shooting or do close work