the RV660. is the obsolete 760 with a smaller screen
an for me.. going from a 5 inch to a 6 .. why bother.
if you 770 is sending you down the wrong roads.. you have something wrong in the parameters you entered. my opinion.
plus the 770 has on-screen route adjustments. no need to download changed routes like from basecamp...
you can plan and adjust routes on screen... tap and drag for different roads or cities. not able in others.
purchase what you like. being software is so personal.. and different.. hard to compare non biased views.
going from Mulligan to Garmin.. was big in software difference.. but worth it in the end for me.
