I haven't used the subox, though this morning as i fired my subtank for the first time and got that huge loud pop... Sigh lol
The provari mods from provape.com are the best feeling quality wise i have seen out there, feels like a very high end piece of gear. My sigeleis feel fairly solid and the ipv and sx mini i have tried holding in the store felt solid too... The provari still takes the cake for me in that respect though.
One thing too, my wife was really put off by the noise of the subtank and found it a bit much, in terms of the hit too, the aspire nautilus was a better fit. I am actually considering making that my travel setup, since as much as i like the subtank... That popping, jeez! The more recently made coils might also solve that, kanger might have had a bad run. The nautilus does give a very satisfying flavour too, just not as "big" of a hit as the subtank or atlantis.
A provari would be 100 to 220 depending on the model, you can get the 18650 extension cap for any of them. With the 2.5 or classic, the nautilus would be good. The subtank mini / aspire atlantis and other sub ohm tanks would need the provari 3.
If you want to spend a bit less now there have been a bunch of good suggestions already. Here is a solid feeling dual 18650 mod that could go with a high resistance coil like in the nautilus or a sub ohm coil in the atlantis...
Sigelei 150W Watt Box Mod - Black, Blue, Red and Silver
If you order pairs of batteries from illumn.com they will give you a case with each, just keep your charged spares in a plastic/tupperware box... They can do bad things if kept in a pocket/purse and contact other metal bits and bobs. That is the big plus of a mod where you change the batteries, you can have 8 batteries and always have charged ones ready to pop in.