Recognition with Saudia was okay:
LHR: Couldn't add it to the booking, no benefits. Got at least fast track by showing the card there. No lounge access at Plaza Premium, they let us in with Amex after a bit of convincing because they were full but we left after 5 minutes, it was so busy and hardly any food was left.
RUH: Check-in guy did not understand that the blue card is not the entry-level card, like on their own scheme. Same in the lounge again, but they let us in after a bit of arguing and showing the ITA website with the different tiers. The lounge was okay.
KUL: Again nothing, had to use Amex to get into the lounge. Tried both Plaza Premium (the Saudia partner lounge) and Express lounge, and the express lounge was far better food offering-wise.
JED: No layover so didn't have to check in. They let us into the lounge after a few minutes. And this lounge was impressive, brand new and I would say even better than the Qatar lounge in Dubai. Only problem was that we were so tired after the 9-hour flight from KUL, on which they had no blankets available and had the dinner service only 3.5 hours after departure - this was definitely the worst out of all 4 flights