I have both.
Empires is great. Lots of good, usable stuff and ideas that allow for a GM to manage a kingdom more realistically, and with more ease. Some of the other stuff is great as well. Factions, guilds and Reknown are great. I would almost call it a must for a detail-oriented GM, or one that wants to add depth to his world.
NA has great ideas, good creatures, and poor editing. I would get it (probably PDF), and cherry pick what I wanted to use, then go back over that and check for inconsistencies system wise. Yeah, a bit of work, but there are at least 3-4 baddies or situations that I am definitely using in my online campaign.
I have a feeling the forth coming Blood Magic may have a better set of ritual sacrifice stuff, but for undead stuff, I think NA is pretty good.
The Moon Hunters are awesome.