Usually, The Watchtower is more like a magazine or pamphlet. The JWs also distribute a publication called Awake!, which is also basically a magazine or pamphlet.
The Book of Mormon would look like a novel. (Mark Twain called it “Chloroform in print.” Heh) Typically, they have a navy blue cover and most people end up using them to support a wobbly table leg or something. I know someone who carved out some of the guts of his, and used the cavity to keep his stash in.
Like I said, it’s a very minor nitpick. I’m an exmormon (and recently dated a JW) and I see little difference between the two, aside from some glaring doctrinal differences. They are pretty much just different flavors of the same brand of Kool-Aid, so to speak. Either way, neither would be terribly open to any sort of thinking that doesn’t already fit within their worldview, although in my experience, both would be very happy to just sit down and chat about religion regardless of whether they agree with your ideas.
One difference between the two:
• Mormons go on missions generally some where around age 19-21, and for two years. During those two years, they do nothing except missionary work – no TV, radio, internet, newspapers, no outside media aside from church-approved materials. Because they have nothing else to do, chatting with you about religion, regardless of your differences, would be welcomed. They are not allowed to hold down jobs while on their missions, date, or participate in any activity that is not directly supporting their mission. (Except one day a week when they prepare for the upcoming week, do their laundry and grocery shopping, write letters home, etc.)
• JWs are expected to distribute XX number of publications each month throughout their entire lives. They don’t go serve missions, per se, in the same way Mormons do. It’s just another part of their lives, something they do on Saturday mornings after the chores are done. They still hold jobs, read the papers, and otherwise live normal lives.
Well, “normal” being a setting on a washing machine, maybe I should say… “and otherwise live typical lives.” 