I have used both the Nautilus and the Aerotank and I've gotta say the Nautilus is just a much better product. I find it to perform much better and the AFC on it is more functional. I've yet to experience any leaks with the Nautilus which is something I've experienced with every Kanger tank, Aerotank included. Also, I ended up selling my Aerotank to a friend and we ended up getting the AFC stuck by trying to untwist it from his Vamo. It took a set of pliers to get it loose but damn was it a pain in the ... trying to manually loosen it.
I'd always suggest getting the Nautilus over any Kanger tank in the market at this time, just try to wait for them to get on sale, I got mine when they were selling for $24.99 so just wait it out for deals to come around.
I'm really liking my Nautilus tanks, but I'm keeping my guard up. As long as the replacement coils are as good as the ones that came with the tank I'll be happy for a very long time.
The Nautilus is probably the best, most trouble free, beginner to intermediate entry level tank, that has come down the Vape line. 5 ml capacity, 4 different size air holes to choose from, that breathes through the side and not the 510 connecter, and able to wick well at 10 watts. Think an all stainless steel tank section would be sweet, but that just my preference. If you don't want to build, this is as good as it gets imho. I bought one just to try out so that I could honestly recommend it to new vapers, and I do recommend the Nautilus.
That said, it does sit in my vape accessory box because I am rba all the way, and it just can't compete with a well built rba tank system. Though have read that it can be rebuilt easily and steps up it's performance some.
Here you go I saw it the other night on ebay a stainless steel tank.
Aspire Nautilus Replacement Tank Stainless Steel | eBay