You should've gone with a Lib Phoenix Series (Lynn/Lando) or T.Rice which have a mellow MTX edge.
Well, I finally received my Heritage and rode it today and so far, I have to say that while they are similar, I have noticed some differences:
1. The Dark Series feels heavy yet the Heritage, although not lightweight, didn't. My 158 was 7lbs using the bathroom scale when I got home, and the 160 Heritage 6.5lbs.
2. The Dark Series would wash out exiting turns when going fast on hardpack, and I couldn't really carve on it. The Heritage almost rides like a regular cambered board on the hardpack.
3. Magne traction is super grippy which scrubs speed off in the flats, and the variable edge that NS uses is less invasive.
It's so early in my ownership to draw any firm conclusions, but so far the Heritage is pretty competent. After riding in hardpack (some softpack) the Heritage has outpeformed the Dark Series. But the Dark Series dominated crud like no other board I've ridden so we'll see how it handles that.