I have always used WIX, then more recently I switched to the Pro-tec filters & buy them by the case (but they are made by WIX too). The Pro-tec is obviously not the quality of the regular WIX filters but they work. However, on my g/f car when I need a quick filter, lately I have been going for the Super Tech because I think it is a seriously GREAT quality filter & appears to be made well. I have heard they are made in USA by Champion Labs...And they are still cheap enough that I am considering switching from the Pro-tec to the Super-Tech if in fact they are as good as they seem??? Thoughts?