The Chromakey filters in Boris Red (there are actually a dozen different keying filters) are excellent. You can apply a straightforward key filter and then apply others to shrink, blur, clean up etc etc the matte. But it's always hard to do chromakey in DV. But I once used Boris Red on an uncompressed HD signal and it was no problem to key out the background and keep individual strands of hair almost...
The motion stabilizer is also very good. It has lots of parameters, but again, its hard to get good results in DV.
It's totally great that Sony has added this bonus, the Vegas chromakey filter hasn't been all that great, and a motion stabilizer is definately something you need once in a while.