I bought one quite a while ago. Heavy as heck, square and sharp edges on mine. Was from "BulbHead" vendor. Charges from USB, using a mini connector.
Holds Charge a very long time. Works pretty darn good. Problem is, since there is no flame that extends out, ya gotta have somethjng that will fit inside the space where the electric arc is. On mine, something over 3/8 inch just can't get into the arc. It is great for lighting thin stuff like paper, leaves, and suchlike. Not sure I would want to use it to light a flammable liquid or gas, unless the fuel is in a thin jet...
I bought the thing to investigate it. I keep it as a distant (fifth or further out) means to get things lit.
If You are New England Batchelor Parsimonious, probably NOT worth it.
As Usual, YMMV, And I am Weird about evaluating things...