The Aspire Nautilus is regarded as the Gold Standard of MTL (Mouth to Lung) style tanks, and it does perform as advertised, but what put me off them was that the coil heads cost quite a lot, not everywhere sells them, and they're practically impossible to rebuild. They don't last very long, especially vaping thicker juices with any kind of colour or sweeteners in them.
For MTL, flavour-chasing vaping, I think that the Taifun GT2 v2 and the Kayfun 3+ are hard to beat - they are some of the 'Gold Standards' of this style of RTAs - you have to learn to build your own coils and wick them, but that's really easy once you've done a couple, and the ability to tailor your vape to your satisfaction, and not having to worry about running out of fresh coil heads makes it all well worth the while IMO, as well as all the money saved.