The Keen Marshall WP is a comfortable, minimalist shoe. There's a lot less between the trail and the sole of your foot in this shoe, creating great sensitivity. It is an excellent choice for cool weather canyoneering, and the version without the Keen Dry membrane is great choice for hot weather dayhiking and summer canyoneering.
Hikers looking for a step up from barefoot shoes may find this a great option. Keen's other popular hiking shoe, the Keen Targhee 2, couldn't be more different. It's much less sensitive than the Marshall, and provides exceptional foot support for rough terrain and carrying loads.