Brad Jensen and Tim Keirnan present a longitudinal review of the Garmin Nuvi 50 portable GPS. What does it do well, and how could its interaction design and interface design be improved?An earlier episode of Design Critique reviewed a TomTom portable GPS and you might want to go back and hear that along with this episode.http://designcritique.net/dc86-longitudinal-review-tom-tom-xl335tm-portable-gpsBoth TomTom and Garmin solve the navigation problem for their customers in ways that are both familiar and different. Neither unit provides a perfect solution, but it's fun to talk about.