Ooh, tricky one. Though I'm still playing the 6th generation Pokemon games these days (including Omega Ruby and Alpha Sapphire), I'm gonna go with Sinnoh here because I like its areas and music more than Hoenn's.

In RPGs, poison that steadily does damage over time, or poison that doesn't damage you at all but prevents you from getting healed until it's been purged (here, I'm asking which one you find harder to deal with).