I only use ball bearing swivels now. After playing around with the barrel swivels I have, I find they dont twist very well under load - and it doesn't take much force to stop 'em from spinning. I also have some crane and roller swivels, which are better than the barrels but still garbage compared to the ball bearing.
When you can grab ball-bearing swivels for like 50c each at the clearance rack at Army and Navy, I see no reason to worry about line twist from a barrel swivel they may or may not be twisting.
I found that article a few months ago, when I was looking for an answer to wtf is the difference between the various types of swivels.
http://saltfishing.about.com/od/tackleandaccessories/a/aa070312a.htmThis was another good article on the topic.