If you have the NX and like it, I'm not sure if you'd like the Nautilus mini or not. I got the X survival kit and like I really really had a hard time with it. I broke the tank immediately by going "Where is the airflow adjustment," it's really hard to see. I put it in my closet with disgust, I really SHOULD get a spare tank or two but I have heard that the X is kind of it's own animal and a kind of "love it or hate it," situation. Etc.
It really doesn't (from what I read) seem that comparable to the other Nautilus tanks. I mean, you may or may not like the mini if you like the X is what I'm trying to say.
Anna