I wish I knew lol, these companies ain't like car companies. You buy a Honda or toyota, and know you're getting a good quality car for the money. I use mostly unregulated devices. I do have an innokin itaste vv, and even though the battery needs to be charged after about an hour of vaping, it's lasted over a year, and never gave me any problems, not one.
The funny thing is, many who buy a car that turns out to be a lemon may never buy a car from that manufacturer again; yet eLeaf sells a dangerous lemon and I bet many who had issues with it will buy the next version. These companies know this...