It's strength is you rank candidates by 1st, 2nd, 3rd choice. So then the problem of do I vote for Nader and take votes away from Gore are reduced.
Additionally the group working for the IRV, also has two other improvements for democracy, Proportional Representation which seems pretty common in other parts of the world.
Or Direct Representation which I'd never heard of before. It allows you to give your proxy vote to whomever wants to be a representative you feel best represents your beliefs regardless of districting.