Do agree that it's kind of pricey for a tank but, you get what you pay for in the end. Really like Phiniac tanks and all the different designs and types to choose from. Even have an option to get a custom tank as well which is great.
Anyways, I did do quite a bit of research on Diacetyl a little bit ago. Really did open my eyes when I started reading of all the dangers that are associated with it and other diketones. Seems like the biggest culprit was butter and vanilla custard type of flavors. I just started doing DIY e-liquid a few weeks ago. So, I know exactly what I put into my juices now and use a lot of organic ingredients.
The polyfill and cotton in cartos is something is something to look out for. Especially, when it gets burnt. So, as long as it is kept moist then there really isn't much to worry about. Oh, there is a thread about the whole subject as well:
http://www.e-cigarette-forum.com/fo...us-510-kr808-4081-etc-filler-type-cartos.html
Overall, I agree that there are a lot of things to watch out for when we vape. It's still unknown about the dangers of long term use from vaping. But, at least it's not as bad as when we all still smoked cigs.