It could go horribly wrong however we do it, and Clemency certainly is more costly to us in the short-term. Maybe some good comes in the end from Clemency.
I don't mind if people pick Justice though, and that seems to be the "safer" option. The only option I'm adamantly against is Punishment, which obviously means the Dementor's kiss.
Actually, now that I see that Clemency is exile, we should probably choose [x] Justice, lest Hagrid repeat his crimes with dangerous creatures elsewhere. That would only compound whatever reputation penalties we get from choosing clemency. Justice avoids this, while preventing Harry from getting too used to destroying people with the Dementor's Kiss (which is certainly an excessive punishment in this case, given that Hagrid did not intend to hurt anyone).
So again, to be clear:
[x] Justice