It's really hard to make a case of copper vs all other bullets, even different copper bullets react differently and have different design characteristics that make them as different as a cup and core, within the cup and core line up you have a plethora of differences as well.
I've shot a lot of Barnes, like a religion I shot Barnes, after seeing some very startling evidence during some elk culling hunts I will never shoot them on elk again, deer I'll still use them sometime, coyotes, antelope but elk never again.
Cutting Edge shot all my game with them for two years, shot almost every animal twice due to small wound channels, suffered from some of the Barnes issues but not all.
Shot probably a half box or a little more of Hammers through game, one elk I shot twice just because the opportunity was there to shoot an elk that was dead on its feet already with a shot from shoulder to hip so test them. WAY more lethal than either a Barnes or Cutting edge, WAY more!!
The Barnes bullet on elk is what made me start looking for other options which lead to Accubonds which took me to Bergers, I shot both Accubonds and Bergers for two years and it was noticeable quickly that any tipped bullet that opened early I lost more meat with, I also ended up shooting a number of bonded bullet hit elk with a Berger but never the other way around. Soon I shot mostly Bergers or Matrix bullets and seen many hundreds of elk killed with them with so few issues it's had to ignore!
I tend to rank bullets by the order I need them to function, first they have to be accurate, then lethality, then meat damage and then I try to get the best ballistics while balancing all the others.
For me I have had nothing but awesomeness from Bergers, I always shoot the heaviest for cal bullets though so I don't think the entire line is good in anything and they really need matched to the chambering.
Very similarly the Hammers have been excellent in the mono design line, they don't have the issues of overly large frontal area early causing penetration issues, they loose frontal area making large frag for extreme damage and large wound channels through the vitals and they maintain the shank in a way that continues on track crushing bone. The Hammers are the ONLY mono I have not gotten to deflect when smoking an elk in the point of the shoulder which really impressed me, also the damage from the petals causing a lot more damage in the core of the animal vs the entrance is much more impressive than any other mono.
Hammer hands down easiest mono to tune to shoot, Bergers I have no issues tuning but I do a lot of them so it's almost see spot run, I really don't see an advantage personally but for many they will find the Hammer a relief!
Hammers and Bergers are my go to bullets, their accurate and lethal!!