The strap that comes in the box with your camera sucks. It's thin, so it digs into shoulder if you're lugging heavy gear, and fails to be super versatile. The Lumaloop's a sling-style camera strap that's designed to be better.
There are three major differences between Lumaloop and your standard strap: The way it attaches to your camera, the way you wear it, and how you draw your camera to fire. It's not the first sting-style strap* but it has a few unique bits.
A standard strap typically attaches to your camera at two points mounted on either side of the top of your camera, so you can hang it around your neck or your shoulder. Lumaloop gives you the option to plug in to either of those two points, or to the bottom of the camera via the threaded mount you'd use for like a tripod. The camera connects to the strap via breakaway lanyard attachment, so you can easily detach it in a pinch, which is one of its unique characteristics. It's sturdy though: My main camera for testing was a Nikon D3s, and a handful of lenses—notably this monster, the 70-200mm F2.8 VRII—so I stuck with the threaded bottom mount for weight reasons.
While you can technically wear any camera strap sling-style—across your chest—if it's long enough, that's specifically how LumaLoop was designed to be worn, complete with a fat shoulder pad. The weight's more evenly distributed, and it felt much better that way after hours of continuous shooting at the iPad keynote. Also, it made it easier to set the camera down to rest between shots at the keynote (holding up 8 pounds of camera gets tiring eventually), since I knew the camera was securely attached to me.
Update: By popular—or rather, Jason's—demand, here's a video showing it in action, so you can get a better sense of it:
The basic design of the strap is—surprise—a loop. Threaded on that is a sliding clip, where your camera's landyard attachment plugs in. So, when you're not at the ready, your camera hangs down to the side, almost like a pistol in a holster, minus the holster. When you're ready to shoot, as you draw the camera up to eye level, the clip effortlessly slides along the strap up to where you're pulling it. Which I think is faster than if you've got it just hanging from your shoulder, since it's one smooth motion from rest to shooting.
The negatives? If you're using the bottom mount, there's no good way to use vertical grip controls, like on the D3s. You also have to position the strap just right when you slip it on, making sure the camera's sliding clip has room to move on the strap, otherwise it's not gonna go very far when you try to pull it up from your waist to shoot. Also, it's expensive, frankly, at $60—especially when you see this tutorial to make your own for $15.
Still, it's a better strap than anything that comes in a camera box, and it was really fantastic to use in the field. If you don't wanna buy one, you should at least consider making one.
The most comfortable way to lug a giant camera with giant lenses
Makes vertical controls tough to get to when bottom-mounted
*BTW, I invited Black Rapid, who makes the similar R-Strap to send me a unit to review and compare to Lumaloop, but they declined.