Okay, it sounds like what you're talking about here is using an atomizer (or atty), with a cartridge (small plastic job with some filler in it) that you stuck on top of the atomizer. That wouldn't be considered a tank, just a cartridge. I'm not sure how popular those things are now a days, and I only tried to use them once.
If the above is the case, and you've only used that and stardusts, then you haven't used a cartomizer yet. A cartomizer is kind of the evolution of what you started with (please someone correct me if I'm wrong). It combines the filler and the atomizer in one unit, and adds an air tube up the center. In my opinion, that is worlds apart from what you started with.
A tank is basically just an addition to the cartomizer. It holds a reservoir of juice that, as you vape, is drawn into the cartomizer thus refilling it as you go.
Watch this video, I think it's a pretty good intro to the whole tank thing....
Those are also one of the tanks that I use. I like the smaller tanks that use regular cartomizers, rather than the dual coil cartomizers.....but that a whole different discussion. I would really recommend trying a regular cartomizer first to see if you like how they vape.
Also, just to be clear I'm not trying to take you away from Stardusts, or put them down. They're a great product, and I still use them, as does my wife. I just want to try and help you on this tank thing. I got frustrated and gave up my first round with them, so hopefully I can help keep that from happening for you.