Depends on who it is, right?

Let's say it's some random npub that hardly anyone knows about and who hasn't built up a reputation. A zap is probably going to be considered more valuable than a repost in that case.

On the other hand, if it's someone who has built up a following and a reputation that is well respected, then their repost will likely be more valuable than their zap. It could also cost them more than their zap would, if the person whose content they are reposting damages their reputation.