I have both Nautilus minis & the x. The X looks great on my mods, but in my opinion the mini is a better vape. In comparing these two, it all comes down to air flow- not a huge difference in flavor. The AF on the X is just ridiculous, but I guess that depends on how tight & consistent you like your draw. in order to get the draw I like, which is reasonably tight (2nd or 3rd hole on the mini), like a cig, on the X I have to close the AFC down to practically nothing - literally just a pin-prick size hole & then its a good vape but it can be tricky to find the sweet-spot - a movement of 1/100 of a mm changes everything. The problem is its top AFC & also top filling so every time you fill you move the AFC (cant be avoided). PITA!!!!!!!!! So, out of those 2 the Mini wins it hands down.
2 days ago, I received my new Digiflavor Siren. http://digiflavor.com/project/siren-gta/
This is a terrific MTL vape, but once again, fiddly AFC. The smallest hole is way too breezy for me (obvious to me that the person who designed this & the X never smoked cigs). However, its possible to close that hole down further to 1/2 or even less & then its an excellent draw. On each hole it clicks into place. when closed down to 1/2 or less, its between clicks so the AFC can move & needs to be re-adjusted often but its not as bad as the X because the AFC is down the bottom. I intend drilling another hole - that oughta fix it.
I have also ordered a Merlin Mini https://www.fasttech.com/product/6131701-authentic-augvape-merlin-mini-rta-rebuildable
Its a similar principle to the Cthulhu MTL RTA in that it has the insertable AF holes of various sizes. Cant wait for this baby to get here!!! I'm hoping for MTL heaven.