Having recently upgraded from the eTrex Legend HCx to an Oregon 400t, a navigation feature I really miss was setting navigation method to prompt.
On the Legend each time I navigated to something, I could force myself to answer first if I wanted to navigate on or off road.
Then I could choose (if on road) faster time or shorter distance. I could of course set it to not prompt if I wanted also.
Personally, since I do a lot of hiking, I liked that option, but even when driving, it is really nice to choose between faster and shorter. I often know which is really faster given a situation/time of day.