Schumacher has done their own comparisons:
http://engine-swaps.com/Pages/ArticlePages/SmokinBarracuda.html
I don't think anyone here has done any kind of dyno comparison. I've got them and wouldn't hesitate to use them on a street motor. And with everthing else being equal (cam, intake, rear, etc) I doubt you would notice a "seat of pants" difference on the street either. For competition, where every last 10th is important, then a full length header would be appropriate.
As always, opinions will vary.