I want to buy a decent map for doing some motorcycle touring or is it best to try and bring one with me ?
You can buy them at any bookstore near Hoan KIem lake but nothing beat google map.
Well, true that Google maps are good.. but you spend data on that one. you could get HERE maps completely free and you can use it in Ofline.. plus it has turn by turn what google maps doesn't got in Vietnam. https://www.here.com
If you are gonna tour then you might want to get a copy of giao thong duong bo vietnam . it's a road atlas of the whole country.