Make sure you do your homework. These units aren't cheap and they are pretty buggy (I've just sent my Oregon 650 back to Garmin after 9 months because the screen was jamming onto a menu item and wouldn't allow me to return unless I turned it off and back on. Garmin have actually replaced the whole unit under warranty.
Note well, this was not a case of the screen freezing, which it also did for a quite a while before I changed batteries from the rubbishy rechargeables that they provide you with).
For reference, there are a couple of community Wikis that might be worth reading on the Oregon 6xx series
and the Monterra
before you shell out your hard earneds. The Discussion Forum
at the bottom LHS of each page makes for very interesting reading in places to see what problems people are experiencing with these units.