Hi, ritopaxi, Buen camino to you, can't wait to hear how it goes for you.
I have walked the entire Norte as well as the Primitivo, and though the Norte is beautiful, for me there is a much stronger "camino feeling" on the Primitivo. This is perhaps because the Norte goes through so many tourist beach towns, all beautiful and many have interesting old churches, plazas, etc, but in August it is prime vacation time, so expect the Norte towns to be jammed. The primitivo goes through towns that may be of the same size as many on the norte (Salas, Tineo, Grandas, etc, are all towns with basic services) but have little or no tourist trade, so they feel more "real" if that makes sense.
There are also some wonderful albergues on the Primitivo -- San Juan de Villapanada and Bodenaya are just terrific. True, the Norte has its share of great albergues as well, with a shoutout to Miraz, but I just felt more in my element on the Primitivo. Lugo is a very nice city, walk the roman walls for sure. And if you think the chance to see 3rd century Roman wall paintings in a crypt is worth a few extra kms, take the detour (not on a Monday, though) to Santa Eulalia de Boveda about 11 kms after Lugo. After visiting the paintings, the caretaker can put you on a path that will take you to the hamlet of Bacurin, where you will rejoin the Primitivo on a path near the beautiful little romanesque church.
I have walked the Primitivo twice now and I am sure I will be back again. Buen camino, enjoy every minute! Laurie