Hi John.
Not being "pickie" here but I do have times when I can't use the Nissan sat nav.
If I'm trying to locate a house or maybe a farm in the middle of no-where and it's too far away from a town or village to be located on the sat nav, it comes up with "un-known address" and gives me alternatives - usually in a different country!
In these cases then the postcode search on my Garmin is the only option. For normal town/village /city addresses then the Nissan unit is a really good one.
Another example. Enter an address, eg., 23 Great Road, London. If you don't know where abouts it is in London ( Ballam, Lewisham, Wimbledon, etc.) it will give you all of them so how do you know which one do you choose? But, if you whack in a post code on a Garmin,Tom Tom, etc., it takes you straight there.
Love the NIssan unit but I have certainly found I need both it and my Garmin.