They are the meanest fish I have ever come across. I have no idea if they taste good, but they are very very hardy. If you ever decided to get rid of them you would need to pump the pond dry or poison it.
Lots of info on them and even several recipes. There is a local lake around here loaded with these guys. When it was to hot to catch much else, we would head over there and fish the spillways for them. Incredible fight. Caught more 5-10lbs than I can count as a kid. Had no idea you could eat them.