Pro's,
Feed'em during the winter and they'll congregate and hang around and you can hunt them. You get pictures of what's there in terms of racks. It's kind of fun too.
Con's they'll go nocturnal on ya and you won't see 'em.
Con Corn's expensive, and it's work, feeders aren't free.
In the end if you want to modify patterns a bit - it's good, especially if you need to in order to have a shot (pun intended) at getting a deer.
