I think a big reason people get away with selling crappy vapo's is that a lot of people aren't comfortable with returning a weed covered vapo through the mail. Alot of places won't even let you return it if you used it for smoking weed for obvious reasons. Its kind of a loophole because technically you aren't supposed to smoke weed out of anything. A good way to avoid a crappy vape is to make sure it has a ceramic heating element. This is probably the most important piece of the puzzle. If it doesn't have the cermamic heating element then you are probably buying a glorified soldering iron which is bad for many reasons. The other important factor is that no plastic is used. The heat is going to release fumes from the plastic which you will inhale, kinda kills the vape/health ratio.