Proportional representation is more competitive

Plurality voting systems, where the winner takes all as in the case of First Past The Post, tend to encourage the emergence of two distinct parties and no others. This is because votes for smaller parties become worthless as dominant parties emerge. The result is that the voter is incentivised to vote negatively, given the choice of two parties, when they might prefer to be represented by another party. This choice is removed...

So we are not voting for our favourite party out of fear that another party will gain ascendancy. This results in campaigns which focus on the damage that will result from the election of the other party, rather than promoting the virtues of each. We vote for the least bad of a narrow choice out of necessity to keep a more feared party out.

Plurality voting is problematic for the reason that we choose instead (of what we might like) the least bad party. There is little incentive for parties to be the best, only not to be the worst, hence they do not provide good Government. They need only beat each other. In a system of proportional representation the parties compete against all others. Hence proportional representation encourages competition for votes.