Benefits: generally hit or miss.

Priority boarding very much depends; in AMS for intra-EU flights (e.g. on 737s) it's often a cattle call.

Preferred seats: with Silver you won't get very far. With Gold... sometimes; they seem to have some random algorithm for determining when. Plats generally do get all the benefits (lounge access, preferred seating, etc).

Expect to use some priority lines, but that's about it. Anything extra is a bonus.

ETA: Make sure you have the plastic card with you. They LOVE to ask for the plastic. I find it silly...