In my opinion there's a lot of variables in play i.e. impact velocity as well as bullet design. I switched from Nosler Partitions when they released their Ballistic Tip with much fanfare; they worked, but they were a step backwards. Around here back then, you could be hunting anything from moose, bear, elk, both species of deer, goats, bighorns, etc within an hour's drive of the house; whether the 30/06 or the .358 Norma Magnum, I just wanted a bullet that would serve well on whatever I was hunting that day. Barnes released the original x-bullet about that time in the late 1980's. I tried them out and they performed extremely well; that led to my brothers also using them and a couple of friends (possibly as much due to the marketing noise going on at the time as much as what I thought about their performance). Everybody was and still is happy with them.
My preference for staying with the Barnes over the Partitions was that I recovered Partitions and could see that they'd stuck together - but they'd shed a lot of the bullet along the way. "Stayed together" doesn't mean "shed a lot of weight but at least most of the core and jacket stayed together" in my world. I rarely recovered a Barnes over the years and the internal and exit wounds told me they hadn't just gone through the game as though a FMJ solid. Both worked - but I liked the Barnes better.
I have never had the slightest problem with their terminal performance on game i.e. failure to expand. But I am not one of the hunter/snipers shooting game out past 400 yards with moderate calibers like 30/06. With the 358 Norma Magnum, I have shot a couple of elk/moose past 400 yards with the 200 grain Barnes. Starting out at around 3100 fps, there is more than enough remaining velocity for expansion out at 400 yards and beyond.
I do have a remaining supply of the old Bitterroot Bonded Core heavy bullets in both 30 and 35 caliber that will last me to the end of my life - they go up the spout when I'm up in the mountains around here in the alders chasing after elk and moose. They were an excellent heavy bullet if you specifically had big critters like grumbly bears in mind.
I don't doubt those who say they've found Barnes expansion to be unreliable. I do wonder what caliber and bullet weights they're using when having those problems and what distances they had problems at. I don't think they're doing anything wrong, but I wonder if the impact velocity of the bullets is below their expansion parameters. I use 150 gr. TTSX in the .308 and 30/06; the 168 gr. TTSX in the 30 Newton; and the 200 grain in the 358 Norma Magnum.
If I'd been having problems with Barnes bullets over the last 30+ years, I would certainly have been looking for something better long before now - it's just a bullet choice, not a religious cult.
There may well be many hunting bullets of other designs that are superior, but I haven't seen any reason or need to explore those options and begin load development all over again.