Originally by: Inconsistent Revelations
Which is faster?
I have just faced this same question, in working up corp standings so I can access the Caldari lvl4 epic arc.
My experience, as a decently skilled mission runner, is that lvl3 encounter missions allow you to increase corp standings much quicker than lvl4 courier missions. Even without blitzing most lvl3 encounter missions can be completed in less time than the lvl4 couriers I was getting, and the lvl3 encounter missions provided as-good or better standings boosts than the lvl4 courier.
I was running the lvl3 encounters in loki (T2 425mm ACs) or tengu (T2 HMLs) ... loki was quicker.
I didn't persist with the lvl4 couriers long enough but suspect they'd provide quicker faction standings boosts ... via the lvl4 storylines ... than lvl3s.
Perhaps I was being offered a nasty set of lvl4 couriers but they were all 1 - 4 jumps into lowsec and around 1/4 of them required cargo-rigs for my prowler to have enough room in the hold (and my blockade runners were all nav-rigged for speed, manoeuverability, and general GTFO). On the upside the lowsec systems involved seemed to be pretty quiet.