Aw Breechplug, comparing crab legs to crawfish is like comparing hamburger to T-Bone. Both are good.....BUT...
Actually, lobster would be a better comparison as far as texture, but the flavor is different. Crawfish aren't as mild as either crab or lobster.
We boil our mudbugs in highly seasoned water, typically with all or most of the following: salt, black pepper, cayenne pepper, mustard seed, coriander seed, dill seed, allspice, bay leaves, fresh quartered onions, fresh quartered lemons, and crushed garlic cloves. The flavor is "robust". Most folks throw some new potatoes, corn on the cob, sausage links, and whole mushrooms into the pot with the crawfish about halfway through the boil. Everything is dipped out and drained, then piled on large trays in the middle of the table. Help yourself - the mudbugs are hot and the beer is cold! (Be sure to suck the heads.)