ABs are cheap (relatively speaking) units and provide great results.
I've seen them to be consistent (at full power) 9/10 times. And they come in pretty colors, kids love them when they see it.
There are some other GREAT units out there that are more powerful and more consistent but they are also more expensive.
Brand new AB800 + a stand will come out to about $350, even less. So for about $1,000 you can get a small studio lighting setup.
The downside is that many folks buy these units and then ask, "I have a portrait shoot coming up and when my flash on camera fires, the unit fires but picture is to dark, whats wrong?" You have to understand WHY you're (anyone) is buying these and how to use them.
Good Luck