It feels pretty good but not as good as front shocks. The screw on top is not an adjustment screw. It is the screw that is removed in order to replace the suspension spring inside. I thought it was an adjustment screw also because of the "progressive" markings on it. The unit comes with 4 different colored springs, each being a different "stiffness". From softest to stiffest is Yellow, Blue, Red and Green. I tried the one that came installed which was the Blue (#2) and it seemed too soft. I replaced it with the Red and I think it's about right for the terrain I mostly ride. The travel on the suspension is about .8 of an inch. It definitely dampens higher frequency (filling rattle) road noise. It's a good alternative to replacing the forks with shocks if you don't want to spend hundreds of $s to do so. I found this for about $60 and it was a 10 min. job to replace the existing one with it.
Hope this helps.