Why should/shouldn’t I dab?
In a chemical sense, well-made dabs are cleaner than traditional cannabis because they're free of plant matter (and the carcinogens that can come from smoking said plant matter). A poorly-made concentrate can come with its own set of issues, however, such as residual solvent, mold, and concentrated pesticides from the plants it was made from.
The main issue with dabs is that lots of people make them at home -- not only is this dangerous for them (if they're using flammable solvents), it's also sketchy and unreliable for the user. If you’re lucky enough to have a good source, though, dabs are an amazing shortcut to getting where you want to be; instead of spending 10-15 minutes smoking a joint of a bowl, you can take a single dab and go on with your day. Also, from a purely practical standpoint, dab vapor doesn’t stink like regular smoke, so it is a little more discreet in general... and that goes for concentrates in vape pens, as well.