The nautilus on a provari 2.5 is now my in the car/travelling device. I think its a great tank similar draw and taste to the kayfun, has never leaked. I guess the coils can be inconsistent sometimes, kanger has had similar issues, i just get 5 boxes max from any 1 vendor and space it out so if i get unlucky it won't be all of them. I have had zero issues so far, just what i have heard... And spacing out purchasing supplies makes sense in other ways anyways to me.
The coils last a good decent time too, with albeit a little usage every day I still seem to get 2 to 4 weeks out of them.
Don't worry, its a good tank and if you are enjoying it even less reason to worry. Might not be a terrible idea to get a second as a backup using one of the sales this weekend if you want more peace of mind?