With Flying Blue Gold since it started, my KLM flights are always priority tagged and arrive first, even to / from long haul destinations. The Far East Airports seem to be more efficient with these issues, and do their part.
Air France varies considerably by comparison, despite the same labels, and could be the same airports, bus sloppy handling.
Tags are only as good as the system and people who have to act on them.
Certainly the use of Schiphol matters, as priority is given and emphasised through the Company, out or on the return. At T4 LHR, KLM always are good, yet other Airlines I have flown into other terminals, Business or First, not reliable. That includes VS, MH BA.
Interestingly, the new KLM baggage policy came into force 14th May 2013. Leaving LCY two days ago, with the Avro85 jets (Cityjet /AF), they were removing hand baggage cases from most passengers. They say this is due to busy flights and small cabin capacity, but it happens often on half empty flights now.
The only way you got to keep them, was if you were Gold or Silver and it had a “priority” tag put on it, or a business ticket (no one!)
All others were tagged and put in the hold.
Most businessmen were all travelling economy (no differences in service) so had bags taken away.
If anyone transferring, they would not get their bag back until the final destination! Not great for an overnighter, unless you hold a business ticket or FFP card.
KLM are V. strictly enforcing charges and allowances now, be warned!