I can't comment about Europe, but here in New Zealand we recognise the FAA PPL/G as a direct equivilent of our QGP (Qualified Glider Pilot). Certainly if you turn up at our club with your PPL/G and want to take our club aircraft up, all we would require is a local briefing, a check flight and a look at your log book. If you are also a member of an affiliated club then you would get club rates rather than public rates for hiring the aircraft.