I'm still using the same eGo batteries I bought 2 years ago, the same ones! For me they last forever but I do rotate several so maybe that's why. I went to box mods thinking they would be better but they're just sitting...should probably sell them. I do really like the Go-go setup and use that along with my eGos. I really like the Go-go clear dual coil cartos with bottom coil that can be easily cleaned and rebuilt. I think the Go-go runs about the same volts as the Kgo and is 1300mAh. I do use eGo VVs now too when I'm not using the Go-go but I seldom use the highest setting. I'm a flavor addict and have to have several with different flavors going at once so a Provari or Darwin never interested me.