What is the best way to get Marshmallow on an AT&T N900A?

As the title says. I'd like to run Marshmallow on my Note3. I use the pen as an imput device so loosing all the touchwiz stuff dosen't bother me.

Are there any good ROMS that work with an easy to follow tutorial for getting them installed? I've seen alot of different stuff online that says Calls don't work or Mobile data.

Have you done it? How does the phone work for you?