Have used the Barnes TSX, Hornady GMX and Nosler E-Tip on quite a few animals, and have yet to be able to tell any difference in field performance, or appearance of recovered bullets. Can sometimes see a little difference in penetration when testing in "media," but not much.
Some of the other monos are designed to lose their petals, such as the Cutting Edge Raptor and Hammer, on the theory that the flying petals will result in more internal damage and hence quicker kills. Have only used the Cutting Edge, and have not been able to see any difference so far--but the have not been able to tell any difference in "killing power" in TSX/GMX/E-Tips that lose their petals either.
Generally all of 'em penetrate somewhat deeper than SOME lead-core controlled-expansion bullets, but as far as killing any quicker with the same shot placement dunno.
