For me the biggest issue is the lack of visual roundabout information. The map itself is too small to stare at on the approach to a roundabout, so I'm having to use a headset to get exit information for the time being.
I also find that the road names seem to get stuck, and sometimes show a road I travelled half an hour ago.
When I did an 8-hour ride last week, I would estimate maybe an hour was spent with no information at all in the instruction box, just a spinning circle. Luckily the voice instruction kept working.