Meadowlark Nighthawk, Heron, Heron i, Blue Heron 2

I am looking for opinions from Meadowlark speaker owners who have experience with the speakers I listed above. I left off the Blue Heron (original model) because of issues with the gas tweeter and no direct replacement option. I am interested in how the Nighthawks compare to the Heron line first hand experience. I am also interested in knowing where if any the dirvers can be replaced for each model.

Happy Listening.