Radio advertisement is honestly not very good. I've had it going for a couple days now and only 1 person's showed up the whole time. They also have stats basically the same as if you just had a couple of your dudes frick-frack anyway, and at least with the second way you have some kind of control over what their stats are gonna be.
Radio advertisement also raises vault happiness. :P
i got an alien blaster in my first lunch box