@furfiend:
Most of the year, I keep my beard pretty short (~1 - 2 cm), so I just shampoo/condition it with my hair. Over the summer holidays, though, I usually let my beard grow out, and then I do use beard balm.
I find it keeps my beard much softer. It also seems to make it a little easier to manage; without it, my hair immediately curls in every direction and looks even thinner than it actually is.
I don't know what the ingredients are, but I assume it's mostly just a hydrophobic barrier to keep the hairs from drying out. If you have a somewhat longish beard and it's not as soft as you like or it's not growing as long as you'd like, I say try it out. Note, you only need the tiniest amount, so it usually lasts a good while.
1-2 cm is not so short.. for me at least!
;D