Am considering the possibility of relocating from the US to the UK for a while (work-related move) but wouldn't want to freeze/waste my NW miles & status.

If I were to relocate, would it make sense to switch from WorldPerks to Flying Dutchman? Is it possible to convert existing WP miles to FD points, and are they devalued a lot in the conversion?

Which program is more restrictive when it comes to mileage redemption for u/g's and awards? E.g. NW allows WBC upgrades only from B to I and from Y to Z; is KL equally restrictive, or does it allow u/g's from more discount-coach fare classes? And are WBC awards easy (or at all possible) to redeem on KL?

Also, what are some of the typical award levels, e.g. how many points for u/g or free r/t Europe/US or Europe/SEAsia in WBC? I tried to look for the latter info on the KL website but it seems that the award levels are posted in a secure area to be viewed only by existing FD members.

Lastly, how is the KL presence in the London area, i.e. flight frequencies to the AMS hub from LHR, LGW etc.?

Many thanks for any comments.