Oftentimes we hold onto preconceived notions like they are rote fact. For a long time the conventional wisdom has been that you must wear heavy duty, high-top boots when you are hiking or backpacking, especially in rugged terrain. And for some people, this is probably true. But not everyone. I am a lightweight guy (5'10"/155 lbs) and for summertime backpacking I have all but thrown out my clunky hiking boots in favor of lightweight trail runners. The trick is to find a shoe with either a full, or at least 3/4 length, hard plastic plate running through the sole of the shoe, usually either nylon or urethane. This is what gives your shoes the extra support you need to accommodate the weight of a pack on your back, and also protects the bottoms of your feet from jagged rocks. The Salomon XA Pro 3D Ultra has a 3/4 length plate, which means it runs from the heel to the ball of your foot, but not under your toes. There are a few different lightweight trail shoes out there with a urethane plate, but these Salomons are my favorite so far. I hiked the entire AT in these shoes (2200 miles in 130 days), hiked the Colorado Trail in them (450 miles in 25 days), have done Class 3 14ers like Longs Peak, innumerable trail runs, etc. They're absolutely great, and I no longer have any use for full-size boots unless there's snow on the ground. Now, that being said, I rarely carry a pack heavier than 40 lbs (usually 25-30). If you're the type of guy that likes to carry an 80-liter pack stuffed to the gills, with your trusty dutch oven hanging off the back, low-top trail runners may not be right for you. Similarly if you're overweight, or have a propensity for sprained ankles, etc. But don't shy away from them just because of dogmatic conventional "wisdom" about boots and backpacking! Lastly, I would not recommend going with the GTX, especially for multi-day hiking. I'm assuming you're wearing these in warm weather, and if you're wearing low-tops in the summer then they're going to get wet no matter what - whether it's sweat from your own foot, rain water trickling down your legs and into your shoes, stream water coming in over the sides, whatever. But the regular (non GTX) versions breath WAY better, and therefore will dry out much faster and be much more comfortable to wear throughout the day. Wide feet, take note - this shoe is also offered in a wide size, although not every retailer carries it.