I have a couple of fs 510s and really like the vapor when the batts are fresh off the charger, but I am having little luck with them holding a charge and have been through too many batteries to keep throwing money at this with the same results! It would not be practical to have anything usb connected and I don't really think I can afford a mod yet. I have been looking at eGo and various tank models and CANNOT decide! I diy my own juice- flavor is a big, fun deal to me. Would really appreciate advice from someone who has been down this road and found a model that has big vapor and long life batteries w/o giving up flavor. Don't know if I am asking for a miracle, but really would appreciate help!