tim blechmann ported some of the ugens to pd as native pd objects i believe... (externals/tb/sc4pd) best to let him speak about that ...
sc4pd is a port of some sc ugens to pd/flext ... it's following the pd dataflow logic instead of the supercollider logic ...
if you only want to have one sc ugen in pd use it, if you want to use the sc language, it's probably better to connect pd and supercollider with jack and osc ...
cheers ... tim