I bought one of those $75 Drager bottles from the ebay seller in phoenix, its at hydro right now. It was in rough condition and Thunderbird said they could test it. If it has any signs of damage on the outside they wouldn't have touched it. They come from the Phx Fire department. I sent it to hydro for piece of mind. It has a round bottom on it too so i need to make a stand to put it in. I couldn't see spending $215 vs $75 for the same exact manufacture date on the bottle, doesn't matter if its new and unused or not.
If I had the money to set aside for a chance i would buy a small lot of those bottles and send them to hydro and relist on ebay they would sell faster. Not everyone has a hydro testing facility near them. The place I went to is 60 miles away from me.
I probably wouldn't hesitate to buy a bottle with the EU version of testing certification vs DOT, if you are filling it at home. I don't believe the hype about not being able to transport a non DOT bottle, because fuel cans from china do not contain DOT markings and yet people transport and fill those everyday with fuel.