I started with a 510, and then bought a Janty Stick.. I adore both of them, but the manual button has been driving me insane.. I know many love them, but my RSD and Poly-Neuropothy causes me to be in too much pain to constantly be pushing a button.. a few months back I bought a 1.2 liter bottle of juice from RoyalSmokers, and since it was the holidays they threw in a Vivo 401 (which they said in an email, was their best e-ciggie).. This 401 is the best e-ciggie I own.. I so adore my 510 and Stick, but the 401 is wonderful.. Great throat hit and I don't have to worry about a button.. What suprises me is that the battery life is exceptionally long.. I'm used to the stick charging forever since I have it plugged in all the time, but this Vivo 401 seems to go hour upon hour even though I am a constant vapor-er.. The 510 only last me at the most 2 hours, but this Vivo keeps on going.. I hope I will be able to purchase more batteries and attys for this, but I have yet to see this companies accessories available since I only want the Vivo brand.