I ALWAYS use the view map, that way you don't have to constantly adjust layers, model view options, etc.
I only go into the project map when I'm dragging a detail/plan/section over to the view map.
The "model" is in the same place, the view map is just a more organized version of the project map, where you define things like layer combinations, model view options, pen sets, scale, etc. Navigating through the project in the project map, in my opinion, takes longer and is more of a pain in the...