The tripod clip is a really nice touch. Kata makes a tripod accessory that attaches to the 3N1 bags but it's extra and not always available.
I've carried a Lowepro Slingshot 200 all over Yellowstone, Yosemite, and other national parks and forests without any problems, but I'd still recommend the Kata or the Tamrac over the Lowepro because of their convertibility/ability to wear as a backpack as well as a sling bag. The medium sized sling bags aren't that bulky when you come down to it, and they'd allow you to carry other stuff (like lunch) or more photo gear. I'm actually on my second Slingshot - I continually overstuffed the first one and the stitching on the zipper finally gave out. I now carry the Kata -30 when I want to take along the kitchen sink so I don't do the same thing with the second one.
I know that the Slingshot 200 can hold a lens mounted that's about 6 1/2 inches. That's about its max - I know it won't hold a lens that's 8 inches mounted, or even in the bag at all, if you have another lens mounted on the camera.