Now you guys have me rethinking my plan to walk another CF... I did my first in April/May 2013. Now, to celebrate the end of my doctoral program, I'm taking August off to walk again. However, with all the craziness that is the Frances in August, I find myself very much contemplating the Camino del Norte.
Anyways, to answer your question, Ross. I haven't walked either of the 2 routes you suggest, but going off of what I've read over the years here are a couple thoughts. As with any Camino, start by thinking a bit about the experience you're looking for. For example, I've heard Le Puy can be much more expensive than many of the other Caminos because there isn't as much infrastructure and many times you'll end up staying in small hotels/B&Bs rather than Albergues. This may have changed in the last 2 years, but if money is a factor for you it's something to be aware of. Le Puy would also have far fewer people, as the Portugese is one of the busier Caminos (respectively). Do a bit of research into the differences of the trails, as I'd imagine (i.e. blindly guess) that the Portugese offers considerably more city walking, depending on whether or not you take the costal route...
Like you, I'd love to hear from the experiences of others as I'm unsure myself which road I'll be taking to Santiago this year...