As with any new product, finding out how to operate it can be frustrating. Being able to turn off the warnings for curves is there.
I too am finding it sometimes is very wrong.
It is frustrating when it keeps trying to send me back and around the route I am on.
That said. I LOVE being able to select "along the route or at the destination" several things such as rest stops, large fuel locations, campgrounds, rv services. This is a very advanced and easy to use feature.
As for seeing the screen I have had absolutely no issues. Often folks don't realize their dash needs to have a cover to reduce glare.
Way more positives than negatives. I have a Garmin Nuvi. Recently I have taken the Rand along in the toad because it has a better Point of Interest information system.