M: It's extreamly comfortable, and does not interfere with paddling. The pocket on the front is ideal for carrying small items such as a signal whistle, pocket knife, etc. The only improvement I would suggest would be a ring sewn on the outside for attaching a glasses case (I wear prescription sunglases) or paddle leash.
K: I love mine, and you can see my wife loves hers' too. It has ample room for my arms while paddling, and is short enough that it does not interfere with my spray skirt or seat back. The front pocket is great. I also like the placement of the accessory holder, as I plan on attaching a dive-type knife to it. It'll be kept out of the way, but easily accessable. (I'm also a diver and climber, and know the value of a good knife when it's needed).