I got a Jinhao x 750 and as others have said the flow is rather dry and the capacity is low.
It seems I have to bear down more than I like. I will try some of the above discussed repairs to the nib and do some more flushing. I’ve found that after filling if I reverse the converter control a turn or so I can just add a bit of positive pressure on the ink and that helps to begin a wet line.
It’s solidly built alright and in the door for about $5. Astonishing really.
I just got it as a test. I have other good quality and vintage pens for reliable writing.