Today, 3 out of five times they worked OK, lifted the tailgate all the way.
Maybe it's only tall people that notice. I'm 6'3" and I think you're even taller Sludge, if I remember right.
I always have to push the tailgate the last inch or two to make sure I'm not going to hit my head.
If you were about 5'10" or less you might not notice that it hadn't lifted all the way to the end of its travel.
If you were very small you wouldn't be able to reach to push it even if you did notice.
The new ones performed really badly first few times. Took a while before they seemed to bed in. Now the door opens perfectly (although the heat did make my last pair work properly)