They are definitely worth the price. What particular info were you looking for? Most have plastic tanks, depending on whether they are vision vivi novas or off brand the plastic may or may not be affected by cinnamon and other juices. The draw is fine to me, and the amount of
juice it holds is enough for maybe half a day for me, maybe less for others. The heads are replaceable, and last for more than a week for some people, depending on what
juice you put through it. I have heads that I've cleaned and used for weeks. I can only speak for two vendors products, gotvapes.com and steammonkey.com. The two vendors sell two different versions, with different styles of heads, so they are for the most part incompatible. If you don't use concentrated cinnamon juices or mint or other juices that would affect a plastic tank, go with the steammonkey.com version, as it should be cheaper. If you do, then I would recommend gotvapes version, as I have had better luck with the plastic on them. If you go with a regular size vivi, and get the metal tank, then you could go with either.