I bought a Nautilus 2 as well, thought it'd be an upgrade from the X but it's just not as good. Airflow is better on the X and flavor on those .7s aren't as good as I heard.
Interesting, I kinda feel like the airflow is the only thing the Naut 2 has over the X. I'm a huge Naut X advocate with the 1.8 coils and 4 mil extension, and have been using 4 of them with different variations for months now. So I got the Naut 2 just to compare. My quick assessment:
Nautilus X- even with the 4mil extension, it's almost the exact same size as the Naut 2, which I found shocking. I guess that metal sleeve makes up for almost 2mls worth. The X is a million times easier to refill, has better flavor (I know some prefer the bvc coils, but I think that's kooky talk

) and in terms of airflow, I think it is smoother, but I'm not sure it's better overall. Also, it's really hard to adjust on my Black ones. Even though that's my standard color, I highly recommend someone getting one of the other colors, since it will make it far easier to adjust the airflow and see what you're doing.
Nautilus 2- I gotta say, I didn't realize how much I missed being able to go down to a super tight airflow that comes from the bottom. Something about it coming up that way just makes it better to emulate a cig in my view. Also, dang, do I miss a 510 drip tip, and the ones that come with it are nice. So I think for those who really like a super tight airflow, the naut 2 has a slight edge. But I think it's a huge pain to fill, only holds 2mls, and uses lesser coils in my view.
So even though I think the X is far better overall, I do think there are some pros and cons to consider. Just for anyone trying to decide between the 2 of them.