YMMD.
Absolutly right - got my 50-Buck-mini 1.33GHz this week. Except from DVD-player and 360p with CorePlayer forget about video.
It will make a nice fax-machine sitting beside my white intel-imac.
So...a 1.33 iBook plays 720P and some 1080P with Coreplayer but a slightly higher specced Mini doesn't? Welcome to the weird & wacky world of PPC!