If you mean the slim Joye 510, its tanks hold no more than a cart used with the atomizer. 1/2 ml. A standard cartomizer (how many prefer to vape) holds twice as much. I really see little point in the 510T tanks. And if you bought a normal 510 you could always buy a 510T atty and 510T tanks if you wanted to try the tanks. if you do buy a slim 510 I strongly recommend manual batteries. 510 manuals are totally sealed metal on the threaded end so you can drip on it with a drip tip and atty, you don't have to worry much about cartomizer leaks etc. Manuals won't turn on accidentally from wind or vibration, and they give you more control over your hit.
If you mean Joye Ego - there are mixed reviews of the tanks. Some like them, some get weak taste, some get leaks.
If you get either tank model I recommend you also but a normal atomizer and carts (and drip tip if you got Ego or manual slim 510). Some people say not to drip on the tank attys and you cannot use carts on them.
And Boge cartomizers are nice cartos for 510, standard resistance only for slim 510, standard or low resistance for Ego
And you need eliquid - lotta eliquid
Notes - standard Joye batteries are 180mah and that is about 1.8 hours of moderate vaping. Nice PCC at NoSmokeVA.com. Joye mega xl 510 batteries are 280mah or about 2.8 hours of moderate vaping but the only PCC is a non-roomy metal one.
And just so you are aware - joyecigs.com is a deceptive site name, not Joye brand, not the same model - it;s some incompatible model