One of my good friends had a 5hp Mariner on his 14' jon boat. It worked fine for 1-2 people and fishing gear, if you werent in a hurry. It was 1000x better than paddling or a trolling motor, but last year he wanted more power so he sold it for a 15hp Gamefisher (a relabeled Force/Mercury, sold by Sears). Based on my liking his boat/motor, a few months ago I bought a new 15hp Mercury for my 14' jon, because I like the speed and power.
But the Briggs & Stratton 5hp is a great motor. If you're not worried about speed, I'd definitely recommend it. This place has great prices on them, and free shipping. www.smalloutboards.com/bg5.htm