I have only killed an antelope with the Barnes XLC (pre TSX) out of my .25-06. I did not recover the bullet as it passed through the animal so I don't know if it expanded fully or not. It did however kill the antelope with the single shot. I have loaded the Barnes TSX and TTSX in a few other rifle calibers that I have and they shoot much better than the XLC does. Sadly I have been unable to test them on any game since I live in Nevada and drawing a tag is like finding a pot of gold at the end of a rainbow.
For antelope I think they are overkill and probally wouldn't use them again. I think I would stick a standard cup and core bullet for antelope. The ballistic tip, Game King, Interlock, SST, even the tried and true core lockt bullets will work well.

As to the Barnes bullets failing, there are certainly some out there that have failed like all bullets. There are certain factors that have to be taken into account when using the monometal bullets. You have to keep them within their operating velocities. Barnes states for reliable expansion their bullets need to be traveling a minimum of 1900fps but many say they need a little more velocity. When you take that into account you will have to study your ballistics and find at what ranges your round starts to reach those velocities and stay within them. I have read on many forums where people have less than satisfactory results with the barnes bullets but when they state the conditions they are all mostly shooting at longer ranges with calibers that are not pushing the bullets fast enough at those ranges.

Match your bullets to your velocity and match your bullets to the game being hunted.
This is my observation and opinion. Others may feel differntly about it and offer up their advice and experience.