For your fishtank or for dinner? They are good for both.
We call the ones from the Murray river yabbies, that river also has huge cod and catfish too. In the early 1900s people were catching 6 foot long cod but not anymore. The best big saltwater crays come from Tasmania, It's cold there and has really fresh clean water. Funnily enough Australian seafood is pretty cheap now as we cant export it to china so for once we can afford to eat our own produce.
We used to Catch yabbies a lot in the younger years then boil them up for a nice feast, they have changed the rules on the traps you can use due to overfishing so they are a bit harder to catch now.
It's human nature to want what you can't have, my wife actually brought me a 3 foot tank on Saturday and I'd love some Honduran red points or nonolutus but you can't get them here and they are on our illegal import list so that's probably why I poked my grumpy nose in here!