An improved hot head that looked like an official V2You may want to check also the first part.
To the credit of my seller, the printer came with a few special improvements from the real machine. To his discredit though, freely using the name Ultimaker is illegal, and I am far from sure that he released these modifications under an open hardware licence, as required by the initial designers of the Ultimaker. As a general rule, consider also that your free support should come from your seller and especially not from the company that got abused in the first place!
Beyond a few pre-assembled parts such as the X/Y blocks or twisted stepper cables and the complex hot end, there were two noticeable differences from the stock UM : the filament feeder had a robust and bigger quick connector (and thus, required specific wooden parts that were initially forgotten in the package), and more interestingly, the pre-assembled hot end proved to be better than the original hot end (but not than the new official and better rev3) !
Here is the fully assembled hot head, and it really looked like what became a few months ago the much better Ultimaker V2 hot end, which is now a standard on real Ultimakers. It is a bit of mystery to me how I got this design so early, as I would not expect this from a Chinese copycat. Anyhow I really enjoyed the design and did not suffer from the issues many seemed to had before the official revision.
The bowden tube comes into the head and conveniently stops at the top plate. It gets secured in a brass quick connector, which itself is screwed into the plywood (it really acks a real nut here).
Then, a second short piece of bowden tube goes from the bottom of the brass quick connector to the bottom one, where it gets plugged into a white plastic clip. This clip has a blue plastic circlips to prevent any movement, just like someone did on thingiverse for the feeder quick connector.
This head gave me only three filament issues in 6 months! The first two happened when I removed the filament probably too slowly : a blob of plastic had time too cool down in between the top and bottom plate, and it would not go through the top brass quick connector. I just had to unscrew the connector, cut the filament and re-screw the brass plug in the plywood. This seems to be fixed now.