Well the eGo has a longer battery life, you can use mega atomizers and carts on it , but it is bigger then the 510. The 510 is more cigarette like, not so good on batteries as far as how long they last before needing a recharge. Also cheaper to buy. Both models will take atomizers or Cartomizers so what ever you want to do there is possible. If you strickly use cartomizers the kr808d-1 has a large following and might be worth a look into.