Ive had my walking foot for about 5 years.....never had a problem with it.
The trick is to guide and support you fabric thought the foot, not pull it out the other end. That kind of defeats the purpose of a walking foot. By all means hold you fabric behind the machine, but dont pull, just have a firm grip and support. Thats how Ive always done it anyway.
I also slow my machine down quite alot too, and this way I dont get any tucks becasue I can smooth them out as I sew, and not take the foot off the gas and think, oh, darn, I just sewed a tuck.