EGo batteries have two types of threading. The outer threading your eGo atomizer fits on is commonly called EGo threading. Note, this is on the outer part.
Inside the post, is an inner threading commonly known as 510 threading. This appears to be one of the more common threading. Lots of stuff will fit on this inner 510 thread.
On my EGO batteries, I use clearomizers, Cartomizers, tank cartomizer combos, dripping atomizers... You have lots of options.
If the iMist supports EGo threading or 510 threading you can use it on your EGo batteries.
Depending on your preference, you may want to try a few different juice delivery systems.
I like a strong vape. The best hit I ever get on my EGo batteries is with a 1.8 or 1.7 ohm carto inside a tank. This hits awesomely.
Generally speaking, EGo batteries produce 3-3.7 volts. The volts produced will diminish over time, as the charge in the battery diminishes. So, if you have options, choose low resistance items if you like a lot of vapor.
Some say low resistance atomizers reduce the life of the EGo batteries, and that may be true, but mine still work fine. I'd rather have a great vape and change batteries slightly more often, than a crap vape and better battery life.
Typed on my mobile. Please excuse typos.