I would suggest that PR tends to fragment the government, while FPTP tends to move everybody to the center.

For example, there has never been a stable third party in the U.S. And the two parties are quite close to each other on most issues--noise on blogs and editorial pages notwithstanding. Perhaps that's because you can poll the electorate and figure out what positions will win the most votes, and both parties do the same polls and get the same results. So the parties split at a point in the center that represents the average of what people think, and as voter opinions change over time that center point changes.

In PR systems, since each small party can get a handful of votes in government, the incentive is to have lots of parties. So after the election, you have this secondary scrambling around that can bring together complete misfits as coalition partners. This system reduces the control of the voting public, because no matter how you vote, the government will in the end be set up by a back room agreement between coalition party big shots.

It seems to me that the former is perhaps better, because at least the voters have a direct say in which philosophy will win--by moving that center point one way or the other.