Originally Posted by atflyer

That is too pessimistic, as the thread also stated. Some practical experiences
- From May onwards on some days there is again availability in J. From September they seem to use every day a J aircraft. Point is like many carriers (AF and KL is doing the same) they are short on aircraft and wet lease from service companies. One of of the leased planes is all Y, which led to the downgrades.
- Several people including myself were rebooked on other carriers with a better quality product or much shorter layovers in e.g. IST as originally planned in JED or Riad. It can take some persistence and calling though to get this.
- So the way to go seems checking at the Saudia website if J is bookable or not. I would recommend anyway booking directly with a carrier if there is a negligible price difference; that avoids they may ask you to deal with the OTA first in case of schedule changes and so on. If for some reason Saudia has a plane change that downgrades you to Y, a fair chance you can get yourself rebooked to something equally good or better.
- If you have long waiting times, Jeddah seems preferable over Riad (from hearsay since I haven't seen Riad). Jeddah has a walk-in airside hotel (for some 110 Euro, can't be booked in advance so you must walk in, not really cheap, but combined with the ticket still a bargain price to Asia in J). Riad has not. The lounge in Jeddah I saw is not really equipped for people who want to sleep, and that lounge seems much more modern as the Riad one if I understand it right.
- The stop in Tunis has pro's and con's. Con are the fairly long waiting times at immigration. Pro is that in my 1 day experience Tunis is an affordable, fairly hassle-free city, with a nice old town. On my way back I have another day, will try old Cartago or a hotel at the coast.
- Positioning indeed will depend where you come from. I could get a return Paris-Tunis with AF for 200 Euro, adding 10 XP. Tunesian carriers can be even cheaper. Overall thanks to the Tunis detour I flew from Paris to Asia largely in J (and a longer journey time) for a lower price as Paris-Asia with other carriers in Y.