I have a Garmin 890RV also. Pro is you input your RV size and hazards are avoided, low bridges overpasses, etc. It will also avoid Google's shortest route down some one lane dirt & gravel roads. Screen size is nice and is pretty intuitive if you use an android tablet you're in.
Con: Cannot change the directions voice. Ours is permanently on Zoe, which we dislike. Garmin said they are working on this. Yeah!
All in all do get one for a RV. You won't regret it.