Never had heard of pankration before today. Looks very useful in real-life situations. Plus, for a fight system to have survived (literally) for a few thousand years, there's gotta be something to it! How long've you practiced?
Personally, I've studies Muay Thai in the past and have just formally begun Kung Fu after having studied it out of a great book: http://shaolinworkout.com/.
The dedication and respect engendered simply by being around the committed instructors, much less my own training, has proved of great benefit thus far.