How's the battery life on this thing? I guess comparable to a 900 mah Twist/Spinner? My Vision Spinner just broke last night... I was trying to pull out my drip tip from the atty to drip, and the whole battery/innards just pulled out of the casing! It still works, but I can't use the VV anymore and I'm a little iffy about how it's kinda... disassembled. I wanted the iTaste VV in the past but ended up just getting a Spinner since it was cheaper.