Beauty dish vs Soft box or Octoagon soft box

What benefit is a beauty dish compared to these other means of diffusing the light?
Why would you choose a beauty dish and if so what brands or dish is good?

A beauty dish gives a very specific light pattern.

A mate of mine calls them an 'ugly dish', because they re designed to be pointed at beautiful people, a gridded BD shows off bone structure beautifully, but due to the shadows it produces it also shows every skin imperfection. He suggests to not use them on ladies over 23.

Consequently they're also an interesting light to show 'character ' in an older mans face.

A soft box is a big soft light source, square or rectangular, so they produce square or rectangular highlights in the eye. An octagonal softbox produces similar light with nicer highlights. Adding a grid to them makes them more versatile.

Beauty dishes are perhaps the worst named of the light modifiers. The name implies beautiful soft light, flattering and pleasant. In reality a beauty dish is harder and often more specular than softnoxes or octoboxes. The beauty dish can be useful when shooting models and skinny people with nice skin but its less useful as an all around tool. In a studio with lots of options the beauty dish can be a great key light with fill from a larger source softening the shadows.

If this is your first modifier go softnox/octo.

Beauty Dish; Large directional light modifier with screen to block center hot spot from flash tube.

Softbox; Large diffused light modifier, mostly without a screen to block center hot spot from flash tube. diffusion panel minimizes hot spot.

Octabox; 8 sided softbox.

Beauty dish with front diffusion sock. About half way to softbox diffusion. Useful outside when wind may cause problems with softbox.

Size matters. Larger modifier, closer to subject offers more gradual shadow to highlight transitions. Beauty dish included, although its still more harsh than same sized softbox at same distance.

Beauty dish was my first modifier. It is something of a Goldilocks option, being smaller than the typical SB or umbrella, and being softer than a fresnel or standard dish reflector. That said, a BD is really a family of modifier because there are many configurations: smaller diameter or larger, silver finish or white, opaque deflector plate or opal glass diffuser, grid or not, diffusion sock or not. Mine is the white 21" Profoto w/glass diffuser, and I often shoot through a silk panel. The only BD universal is the perfectly circular profile.

I'm really digging the beauty dish. Mine is the Hensel 22" silver. Sturdy, easy to mount, and doesn't blow away in the wind. But where it really shines is in the crisp contrast it gives me right off the bat, as well as the high efficiency in terms of power that allows me to shoot at very small apertures (or wide apertures with a 3-stop ND) with my 500J monolights. Sure, I get deeper shadows than with a large softbox, but considering the average of the population nowadays, that's a bit of a blessing since it makes it easier to make people look slimmer by means of high lighting ratios.