After a 3-year 'gestation' as a QFF Silver/OW Ruby, I share virtualtroy and JuPe's posts.

J check-in counters, yes, but priority tags, no. Of course, you'll get priority tags if you're travelling J or F.

One exception is BA (as noted), they don't seem to like Rubys polluting their J queues. At LHR, they always have a person at the entrance of the J queue to turn away people, including OW Ruby.