The most commonly used sand-type-fill is called 'heavy sand'. Its often a specific type of mineral, eg 'zircon', it's not sandbox sand or beach sand. See, eg. for more information.
https://www.6mmbr.com/sandcomparison.html
The other types of fill are only used when necessary. Beads is typically plastic bean-bag style fille. This is a good choice if you are shooting in the rain. Alot of original (large) GCs with beads were used at one time. The other fills are 'light' fills, and specifically are less heavy than beads, with the tradeoff of being less stable (with less on target accuracy).
The beads also are less absorbent of rain-water than sand. For larger OG version shooting bags, the beads can make sense. Its typically used with a cordura cover. This steup is considered to have decent portability, all-weather robustness, and long-term durability, this makes more sense to carry for field use than a zircon-filled waxed canvas model.
The waxed canvas is thin and easily torn, and the heavy weight of the zircon sand puts stress on the stitching over time. Its considered a consumable item after a couple years (ie the OEM wont fix abrasion/wear type damage more than once IIRC.)
For competition/PRS use, the schmedium with zircon type "heavy sand" fill is the best performer by consensus. If you are .mil or a hunter, and using a shooting bag in the field, etc...then a cordura+ beads or lite fill is typically considered more appropriate.
