I went from a standard 510 to start with and got tired of havng to use and charge 3 batteries or more a day. I then tried the Riva/eGo and it was a vast improvement, from Litescigs USA or Libertflights, it is a great realiable kit and you get 2 650 mah batteries and you can use standard 510 attys or LR attys of 1.5, 1.8 or 2.0 ohms and they do great. You get about 6.5 to 8 hours per battery depending on how much you vape, it also comes with a 900mah, (100mah eqauls about 1 hour of vaping) and they can get an 1100 mah as well. You can use attys cartridges, cartomizers or drip for more flavor. That lasted several months then I tried the Provari, a major step up, it is a little bigger, but uses a larger battery then the ego, is cheaper by AW IMR, like 1100 or 1600 mah and the biggest and best battery with an extension cap of the 18650 ASW IMR, gives anywhere from 1 to 3 days depending on your vaping, uses the 510, standard, LR or HV 3,5 ohms or other attys with adpators, is technically very advanced ..has a digital readout of atty ohm rating, battery voltage readout, battery charge, and lots more. There is variable voltage so you can adjust how powerful you want to go from 3.7 volts in 1/10 increments up to 7.4. There is the VV Darwin as well that does the same and is a longer but thinner unit. Finally you may want to graduate to a juice fed mod like the ferrari Ali'i, hard to get, or the cadillac the reo Mini or Reo grand, very good and no hassle with carts, cartos etc anymore. Provape sells the Provari, Nhaler the darwin and Reosmods the reo's. They are all really top of the line and it depends on your taste, budget and what you like! Check them out, they all have their own threads and read about them! Good luck!