No major reason for us; and would have been happy to go with Pz if it was the earlier/available option, but we'd read from a few sources and studies about the Pz+Sv combination appearing as [potentially] more effective against Omicron infection, and with both shots available at the time we needed our booking, we just went for Moderna.
We had no side effects with Pz (either shot), and we figured as both are the same type of vaccine, the differences in terms of side effects on the smaller booster dose would most likely be negligible.
Just back from the pharmac_ a little while ago, actually - 5G signal strength back to 5 bars for a while
Didn't feel the jab (thanks, nurse!), no site soreness, and no side effects to speak of at this early point.
Cheers,
Matt.