I've not found the 3 year old MIB1 NavPro I've got to be too bad. The biggest problem with it is the reliance on RDS traffic information. Its not even that RDS is actually poor - its just that UK RDS data is pathetic - not enough data and it being poorly updated (time to "see" a problem can be 30+ minutes and then either clearing it hours after the problem goes OR clearing it before the tailbacks have actually gone).
That's not VW's fault though.
On the continent the system works REALLY well because they actually bother to have accurate data broadcast.
I'd like some better traffic data, but MIB2/3 offers that without resorting to Google Nav. From what I've seen running a smartphone nav instead can be a bit of a double edged sword.