As you can see the Steelfist Swiss match the Perry late medieval figures very well. In the first picture you see a Perry WOTR metal knight with a Swiss head, a Swiss figure with a Perry plastic head and a Swiss figure "out of the box". The halberds are esp. nice and come gladly a bit longer than the short Perry polearms.
All in all a very good set and I am certainly hoping for more Perry late medieval "mods"! ;-)