I have not fished the Native Watercraft Propel but have evaluated them in preparation of maybe buying one. The hull bottom has an excellent design that should make it very stable. I liked the trolling motor model but both models look good. The prop design of the paddle model may be more efficient than the Hobbie style of paddles.
The one negative that I saw is that both the Propel and Volt models stick pretty far below the bottom of the boat when in position. You will loose some of the shallow water ability with the motor or prop in the water. That is not all bad because for the times you want to fish really skinny water you can use the paddle. I think they are a great design and would work in a lot of different fishing venues.
You can easily remove the Propel system if you want to lighten the boat for loading. The Ultimate 14.5 only weighs 68lbs so that shouldn't be that hard to load.
Native Watercraft Ultimate 14.5 Propel
Native Watercraft Ultimate 14.5 Volt