Are priority tags only given to those first/business pax who paid full fare in CX, or are they for Op-ups as well? And what exactly is the advantage of having the "Priority" and "***** Class" wordings on those tags?

First part, I'm not sure about the op-ups. By and large most op-ups have status, but still interested to see what happens (say a GO gets a J-F op-up...does he get F tags? I don't know).

As for the advantage of the priority and first/business class wordings, at HKIA CX does a pretty good job of having the F class tags shoot out first, followed by J class tags, and lastly by non-tagged bags. Certain outports are better than others but HKIA is usually quite good at getting CX's priority tags straight. I presume it must have something to do with where those bags are loaded on the plane (maybe they're loaded in last, and together?), and then the HKIA ground agents are very good at offloading the F tags first, then J tags, then non tags. This is pure speculation, though.

I can tell you, as a DM so I have F class tags (and use HK ID, so I go through immigration in a matter of seconds), I rarely wait more than a few minutes for my bags when flying CX. My bags are frequently among the first five to hit the carousel. It really increases the appeal of checking bags, since I know whenever I'm returning to HK checking my bag is virtually the same amount of time as carrying on. I'm a huge fan. I contrast that to a recent flight on QR back to Hong Kong, I waited for my bags for nearly an hour....despite having J tags!

You get the tags for the higher class to which you are entitled either by travel in that class or status. So a Gold who gets an op up at check in gets F tags.

Whether priority works depends entirely on the airport. HKG is fantastic; other European ones are completely random.

The F tags work well for me at BKK, HKG, JFK and LAX. My bags are usually in the first five on the belt, never more than 10th (except once on a very tight connection LHR-HKG-BKK when my bag missed the connection and was sent on the next flight two hours later, -- I just waited by the baggage claim belt).

Not true!

Based on numerous flights from HKG and ex-HKG, bags are tagged based on the fare class you purchased. So if you purchased Y, you will not get priority J tags nor lounge access, if upgraded to J at check-in. They usually will write "no lounge" on the boarding pass.

Different agents handle it differently (although I suspect that there's something written about benefits for op-up'd pax in the CX Passenger Handling Manual). I've had a friend who is GR and he got op-up'd at check-in and they still offered him a Lounge Invitation (I guess out of goodwill) - not sure about priority tags.

I wonder if Premium Economy would have priority tags as well...

I can foresee 75% of bags have some kind of tag or another with DM, GO, SL, then straight F/J/Y+ fliers....

I'd just say no tag for Y+ at all. Continue to only have them for F and J on 4 class flights, otherwise only F and MPC elites get them.

I doubt CX will have priority tags for Y+. Even BA Y+ doesn't have priority tags.

My experience with F tagged bags in HKG was they arrived on the carousel before the buzzer sounded and the (regular, non-tagged 100's of) bags came out. After I left immigration which only took maybe 10 minutes I was waiting at the arrival carousel that had what I thought were orphaned bags from a prior flight and upon a closer look after they went around a couple laps, one was mine. By the time I hit customs the regular bags still hadn't started to come out.

In BKK in April my F tagged bag was out about 300th. I mentioned this to the CX BKK station manager then, and yesterday it was #5 out of the pipe along with other F tagged bags and in a small group of maybe 15 bags total followed by no bags at all.

It was less busy but maybe they pointed out past performance to the ground staff and it got better. All I know from opening the door of the aircraft to being in the terminal took 20 minutes most of which was walking.

From my limited J to F opup experiences, LAX->HKG twice, both got F tag and F lounge. One HKG to LAX opup, F tag but only J lounge.