From what I understand (my knowledge base on this is a couple years old), a 510 is a small, cigarette-shaped and sized (about the length of a 100mm cig) with interchangeable batteries, atomizers (the burner), and you could use the one I bought a while ago with pre-filled cartridges, cartridges you could fill yourself with
juice, or you could drip juice directly onto the atomizer. It's more of a model than a brand, lots of companies make 510-style parts. But I think the major drawback is that you're not going to be able to add a bigger thingamabob, which is what you're really going to want...
510 is also a thread pattern for threading batteries and atomizers together - it's a fairly common one, and all 510 pieces are interchangeable with others.
I tried them a while back, found the dripping and the self-filled cartridges too messy and the tiny batteries ineffective at giving me enough vapor to mimic smoking, and gave up. Came back to the
vaping world a few weeks ago with an Ego, which is a bigger device with tanks you can fill with juice that last for hours or days depending on your use. Love it.
Your mileage may vary, and someone else may come in here soon to tidy up any points I've missed or misinterpreted. Good luck!