I've packed with an Eberlestock, Full Curl, Kifaru, and Stone Glacier.
Meat is heavy and elk are big. Packing them out of the mountains is hard work and if you don't do it for a living you are going to be sore and it will suck unless you buy a horse.
To make it as comfortable as possilbe you need a good suspension, adjustable pack that rides well and functional load lifters. All that I've used but the Eberlestock have that . The load lifters don't have enough angle and they just pull the weight closer to your back not lift it off the shoulder. You will get more shoulder fatigue with that pack but it still works and doesn't "damage" you as many would try to have you think.
There is no gravity defying pack out there that makes 80lbs feel like 40. You can shift how it carries but the only way to make it lighter is to decrease the load. Pack threads are like everything else on the internet, everyone can shoot sub MOA groups with their rifle at 500 yards and all bowhunters can shoot 3 inch groups at 60 yards, take it with a grain of salt. Packing critters out of the mountains is hard, unforgiving work.
I no longer use a full curl because of the weight of the pack and day hunting comfort. Not because I think others haul heavy loads better.
On my typical hunt we spike camp in and hunt for 10 days. Unless we are packing meat I have a moderate load for a couple hours each way twice. Most of the time I'm wearing the pack is for hunting. Lightweight and comfortable for day use are more important to me than dedicated load hauling ability. Even if we pack meat, I spend far more time with a pack in "daypack" mode than I do hauling. I base may pack decision accordingly.
For me there isn't an appreciable difference between the SG, Kifaru, and Horn Hunter in that capacity. I based my choice off of the other factors. There is a huge difference on the internet with the fan boy culture in back country hunting. It is no different than the age old Ford, Chevy, Dodge, etc debates. Horn hunter isn't an expensive cool guy toy.
Since you have used the Full Curl, you should have an idea of what you like and don't like about the pack. You should have an idea about what is important to you in a pack. Sit down and make a list of the things that are most important to you in a pack, it doesn't matter what the internet crowd thinks. Then look at the different brands and see which fits your needs and wants.
If you simply are upgrading based on packing out one or two elk a year I don't think you'll find a huge benefit over the Full Curl.