3rd they increase BC, I would go ttsx in 180 grain.TTSX in the 168 or 180 grain if I had the option.
I've had great luck with the TTSX this year, and if nothing else the plastic tips do 2 things. First, they act as a wedge to help open up the bullet. Second, they keep the tip from deforming in your magazine or with any rough handling.
I actually prefer the tsx myself. I have shot hundreds of each and lots of animals with each. I don't feel the tip helps expansion at all. The tips on the ttsx will deform in The magazine the tsx doesn't seem to.
They are the exact same in my opinion. The only reason i prefer the tsx is the tips dont deform