How good it is depends on the dream. They do tend to be fun...unless they're nightmares where you're lucid for a mere three seconds, or however long it takes to get out of a pickle.

Addiction? It's not like heroin...you'll want to have more, but I, for one, don't particularly want to sleep all day. I may sleep an extra hour or two, though, if I want a lucid and am frustrated with not having had one.