Summary: Just keep in mind that if you buy this product, you will not have the capability to load any Mapsource data, or any map data at all. The unit does not come with even a rudimentary database, and although there is an optional (and riduculously overpriced) PC interface cable, you won't be able to upload anyting into the GPS unit. No street maps, no topo maps,... nada.
Summary: I really love my Garim GPS 12. It is easy to use and move between screens and features. The Summit is not as easy to use. It is not as convenient to identify way points, does not work with mapping software and its display is to simple. It was not a step up but sideways. I use it in conjunction with my GPS 12 mostly just to keep the track log.