What case is better? So long as it isn't the nut case...
Stock there are 2 basic cases to look for. The standard, or the Nodular. The Nodular was a special casting process that made for a better casting. When they were making them they used an "N" in the mold so later they knew those were the good ones. The N in the mold is mirrored after casting, so you see a raised backwards "N" between the webs above the pinion. In stock form, that is the difference in materials in the castings. There is also small and large carrier bearings, which is completely different than small and large axle bearings.
Going into the aftermarket, anything will be as good or better than a factory Nodular case. How much better? I don't think anyone has ever done real testing of that. You are looking at cases that are way stronger than most standard internals that will go in them, so it doesn't really matter. The aftermarket offers and even larger carrier bearing option for use with aftermarket 35+ spline axles as well. And aluminum carriers if you want to take off a little weight, the basic ones are not that different in price from the aftermarket iron ones as well.
There is also an upgrade on the pinion support as well. While not technically part of the carrier, it does bolt to it and is part of the gear setup. Daytona pinion support adds larger bearings. It was named after the Daytona speedway where sustained high HP loads were cooking the pinion bearings. So they made a different pinion support with larger bearings to support the sustained high loads. It is a common upgrade in building a custom 9" housing, almost standard these days with anything using all aftermarket parts.
A stock carrier will generally do just fine in a Bronco. Hot motor, plan to run it hard? Getting a diff built anyway, any of the aftermarket carriers will do just fine.