[bigendbob]

In a strange way I would be concerned if it came down slow.
It could be air in the system, try re-cycling a few times as I would assume like all hydraulic systems it use the fluid to dampen the movement.
Might move faster on hot days ( when you are more likely to lower the roof).

This vehicle is a rattle fest. The noisiest car I have ever had. Having said that quiet at the moment.
Lots of silicon spray around the dashboard and roof seals. Rear deck rubbers in the corners and the wedge that locates in the rear deck.
Extra rubber where the roof sits. Any visible contact points have fitted some thin rubber.
Sun visors have fitted rubber pads. Even the vanity mirror covers rattle!