The protank II with the adjustable airflow base is great if you prefer a long, cool, airy draws. This is not to say that protanks are not finnicky. They are and there is a learning curve. You have to learn to clean, manage and even rebuild the heads sometimes. For some that is a dealbreaker. The upside is that the replacement heads are cheap and easy to find. I use the protank II every day because I'm never in one place and, if you set them up right, they don't leak and are relatively durable. (The nautilus is clearly superior but the replacement heads are sometimes hard to find and they will cost you a fortune. Also I'm worried about breaking the glass.)
Something like the kayfun lite will work well if you're willing to learn how to rebuild. You'll easily get the best vape from something like this. Were I more stationary throughout the day, say working at a desk primarily, I would use something like this. But if that were true, a cheap, tankless rebuildable dripping atomizer would arguably serve the purpose. Or, really, a REOS mod set up would rock.
The IBTanked are great carto tanks at a good price and can accomodate a warmer draw. But again, you'll have to find some cartos that you like and make an investment in them. Once you find the right carto, this is probably the most no-nonsense and versatile option provided that you're willing to shell out for cartos. Plug in the carto, fill the tank and you're set.