Dear Colleagues,
I would have thought that "descend now" or "descend at pilot's discretion" would be less ambiguous than "descend". Given the latter instruction in UK airspace, I always query it if I (or aircraft) do not wish to descend straight away. Most Continental ATC centres however do mean descend now when they say descend, so I don't even bother asking.
In my experience a few pilots I have flown with have a poor attitude to ATC and treat them as subordinates. A good example is weather avoidance, where these guys will Tell ATC they are going right 10 degrees" rather than asking or even offering a choice of turn as I always do if I can.
UK ATC are the best in the world in my opinion, nobody else can shift as many aircraft through such crowded airspace.
Keep up the good work guys,
ATB, PTC