I have used the twistin both 650 and 1000 mah size, but have found that the vision spinner is a much better unit,also has 1100 mah size battery, the twist did not last to long,for me only 2 1/2 mo. so far the spinner 3mo and still going strong, I have both the 1100mah and 900mah size...plus they are cheaper and you can use the same charger, discountvapers has good price on these, i have move on the the larger vv
mods that use 2400 mah batterys , but still use the spinners as much, hope this helps...