3.8v -3.9v runs about 6.5w-7.25 roughly depending on which coil 1.6 or 1.8ohm you have in. For those used to 6-7w on the older style eGo VV/VW type batteries or running 3.8-4v on average the Nautilus is definitely a large move up from a Smok Tumbler, Trophy, Vision Victory, Innokin IClear anything as far as boosting both flavor and vapor production with much better coils to start off with.
I've had some coils now having seen a few months of light to moderate use showing Aspire puts more into their stuff. I have also had the chance to compare the Nautilus Mini as well as 5ml version both using the exact same coils up against the Kanger Aerotank and Aerotank Mega tanks with the Nautilus tanks coming out on top as well as comparing the Atlantis sub ohm tank also by Aspire up against other sub ohm like the Eleaf Melo with Aspire out on top each time.
The first glass tanks for me came back in late 2012 early 2013 when getting the first larger then 1.6ml CE2 clearomizer or refillable blanks for the cig alikes back then. Those were tried out on the first Vamo V2 APV prior to getting into the eGo-C 650 Twists that came in a starter kit. The first glass were the DCT type that leaked like sives despite the second both by Smoktech back then having a fasten on type lock washer for a supposed better seal that didn't! Those proved worse then the CE2 dry wick issue common place 1.6ml clearos that simply had to go at some point only to be seen late 2013 once into the larger SMOK and Vision tank compared before.
The "Good Stuff" like the 5ml 6-18w operating range Nautilus came last year as the newer more powerful compact mods were first coming out and then the first sub ohm. I still run a few Tumblers with specific flavors kept in those while having moved onto the Aspire tanks for the most part for quality as well as flavor and increased vapor output that does seem more of a better smoke replacement from the improved vaping experience point of view. You first have to get used running somewhat at higher watts to understand that doesn't always mean you end up with a hotter vape.
The increased vapor will tend to sooth those who were more of the moderate to heavy smokers while the smaller lower wattage and VV stuff would seem to fit those who were either the light or occasional smokers who tend to look for too much. For those who still smoke and vape they will be the people that can also benefit from looking at both the Nautilus and sub ohm tanks to bolster things to their own personal needs and preferences. Just remember the way the flavors wick up easily or rough will also have an impact on overall performance regardless of gear. Menthol flavors generally tend to run 6,7, 10-15w and higher on sub ohm gear from 15-13w while other sweet non fruit and berry desert types can run 20, 30, 40 upto 50w at times. On the Nautilus they run well at 6-18w adjusting by individual flavors while I seem to average about 13-15w with both menthol and non menthol. The 5ml Nautilus also gets treated to epipe both mech and 5-15w regulated mods here due to it's reliability and much longer life seen with the coils. The older BCC stuff would typically see about two weeks max with any coil even when trying to replace factory cotton with imported Japanese cotton and not working out well.