Depends on the lure action. Spoons for instance would require a barrel swivel, otherwise line twist is certain. I trolled a sppon one direct-tied, for about 15 minutes. Reeled in, and cast out again and woah! Man I've never seen a birdsnest quite that big!
I prefer direct tied for any lure that doesn't have a twisting action to it. But if it spins, go with a good barrel swivel for sure.