Ah there is so much to explain ...
A lower ohm coil like what comes in the Subox kit - 0.5ohm coil (subohm) requires more wattage and will give out more vapour. The wattage rating is 15W-60w, the mod, or the device that powers the coil has a variable wattage so you can change it to your desired vape, usually within the range of the coil, I find 35 watts to be the sweet spot. The 0.5ohm coil is also designed for lung hitting, where you draw the vapour directly into your lungs and then exhale, it sounds a bit weird I guess but becomes very natural and is the only way I vape now.. Also the tank has an airflow control where you can open or shut of air, for lung hitting it is best suited to wide open, airy draw, lung hit..
A higher ohm coil also comes with the Subox kit - 1.5ohm coil requires less wattage and will produce less vapour. The wattage for that coil is rated 10W - 26W. The 1.5ohm coil is designed for mouth to lung, like you would smoke a cigarette, where you draw the vapour into your mouth first and then into your lungs. Usually you would close off some of the air flow, tighter draw, mouth to lung.
This is why I recommended the Subox as it has something for everyone and it gives you the option for both styles of vaping, or the option to at least try both..
You will need a single 18650 battery, the VTC5's are good but I have used a Samsung 25r and that worked fine too. I would suggest you buy a separate charger, the on board charger, I'm just not comfortable using, the Nitecore i2 is a decent charger for the money.
You can buy separate 5 packs of coils when needed
Something else to be aware of, for the 0.5ohm coil, you get more vapor and more nicotine so you will need to reduce your nic to about 6mg if you are lung hitting, also the pg ratio in the e liquid shouldn't be too high as this will cause to much throat hit (kind of burning, harsh feeling).. With the 1.5ohm coil, you would need a higher nicotine in your e liquid when doing mouth to lung as you are gettting less vapour and less nic, I'd suggest 12mg (Personal preference)..
Why I'd recommend this over the Nautilus is mostly from what I've already said, the Nautilus will limit you more and you will probably end up buying again.. The Nautilus just has way less options.
I hope this helps somewhat