I have been on four SWU/SSWU upgrades this year on LHR flights, and was op-upped once for the same. I noticed no difference in service between myself and others on the flight. On the op-up, I overheard the FA's talking about how they were going to make my pre-ordered VGML more fancy for a J service, which was kind of nice. I have noticed, however, that when I have my professional title on my boarding pass (Dr.) I have received extra friendly service versus when it is not there (for some reason, the London Pass does not allow me to put a title in; in any case, the title is on my profile from the days when it was a novelty for me and I should at some point take it off--I am not an MD so it is probably better not to have the title on when in flight as I wouldn't be much use to any ailing passengers!).