There's really nothing much to say about the design of the Nuvi 1390. It's rectangular and rounded; new elements are restricted to the piano black bezel, rubberised back and an added dash of thinness. Garmin keeps on telling us that it's an engineering-led company, so it's entirely likely that the design department consists of a man who's rapidly becoming the world's greatest expert on baseball statistics.
Within the 1390's neat, but non-descript body, there's a bog standard 4.3-inch touchscreen with a matte finish. Except for the power switch along the top edge, the Garmin is controlled entirely via this 480x272 resolution screen. The windshield mount is pretty compact, easy to set up, sticks soundly to the windscreen and offers plenty of adjustability when affixed.
The interface has also only received a mild tweak or two, with the main menu gaining a few reflections and a few spiffy animations for that extra bit of spit and polish. Functionality-wise, it's the same Garmin interface that we know and love.