IDk about the newer brents, but on a 800 and a 1000 bushel Avalanche cart at work (I believe both were 84 series?) the auger support broke out from the bin wall. We are encouraged to run them hard though to keep up.
IMO advertised capacity must be heaped and not level, still takes two trips to get the truck full which IMO is a huge waste of time.
So while I dont have any experience with other modern 2 auger carts, and Brent still makes a good cart, I would not fear looking at others.
Our farm purchases a combine soley on its ability to do an excellent job in all of our crops, while being fuel efficient, reliable, ruggedly built, and easy to repair. That is why we choose a Gleaner.