I don’t have any personal experiences with any of these crew finder sites but I know lots of people who’ve used them. The catamaran designer I appreciated under met his wife through one. She had no prior sailing experience but was willing to learn, and he needed crew to do a Caribbean crossing, and that’s how the story began for them like 25+ years ago. They still sail together all over the world.

The other advice is good too. Just walk the docks and ask around. People love talking about their boats.