I keep a 5 footer in the back of my JKU. I would never store one outside. The pins will rust and you'll have no success trying to use it. Even the one I have inside my rig rusts a little bit. I have had to lube the pins twice this year. I can say that in the driveway, or off of the side of the road, the stock jack with a block will suffice. Off road, in a molly with a popped bead, there's no where to even put the block. I have used my hy-lift for extraction, tire changing, and used the post one time to repair a broken tie-rod. A hy-lift to me is like American Express. Don't leave home without it.
Note: I have modded Rubicon rails, with a tube hoop welded to it. And steel front and rear bumpers. So I have no problems finding a jack point.