I've been using this now for about 3 months and overall very pleased with it. The app works really well and is quick and easy to use. I love the simplicity of it and the arrow is very accurate and clear, which means you take your eyes off the road much less than a classic sat nav or phone based system, a very quick glance tells you what you need to know without processing a load of other information which, while it might be nice to have, imho is totally unnecessary when you arrive at a junction and only want to know left or right. Battery life is amazing, I only charge mine once every 2 or 3 weeks!
The only things which could be improved are the dots left and right, which indicate which way to turn at the upcoming junction, are very small and (without my reading glasses) are not clearly visible to me. This is not a big problem, as when you are arriving at the junction the arrow is already starting to rotate in the direction you need to take.
The other thing is the app does not offer the ability to route via a waypoint, so you need to enter one destination at a time.
What I really love is the compass mode which, when you set a destination, will keep pointing the arrow in the direction you need to be heading to reach it, giving you the freedom to choose which roads to take. If you have time and are just our for a ride but want to end up at a certain place this is brilliant, you can choose any road just because you like the look of it and eventually it will guide you to your destination.
I'd definitely recommend it and for the price I reckon it's great value........hope this helps