Ah, the luxury of Omega. One night we were southbound from GLA to PMI and found ourselves on top of a company a/c out of MAN also to PMI. We could see them a couple of miles ahead & below. There we were, in the twilight evening, trudging towards BHD. Then, as if it was Christmas, ATC cleared us both direct BCN. Oops, we didn't have Omega. Our mate below accepted the clearance, and we hesitated a bit. Quick chat to our colleague to confirm they had a good idea how to get direct to BCN and we just followed. He also said his radar was a bit iffy, so if we could ping ahead for both of us he would 'pathfind' us to BCN.
Happy days.
regarding different variants: how things changed. In 90's, under JAR, a mate of mine with Air Belgium was swapping B733 for A320 in the same week.