I'd like to know if these two names refer to the same type of juicer and if not what exactly is the difference?
They mean the same thing. They are the opposite of centrifugal juicers.
I have an Omega J8004 masticating juicer which is great. I think the new Omega model is the NC800 HDS, which I have not tried yet.
Thanks calumin, just had to hear that from somebody to make sure.