Yes, there is a quality difference that typically affects how long the plug or jack lasts; there is usually not as much difference in the sound quality as the hype would have you believe, except that in reality as parts break down they start to sound crappy. So a brand-new cheap part will usually sound just as good as a brand-new expensive part, but the expensive one is more likely to keep sounding good for a longer time, while the cheap one may start to break down and sound crappy for a while before it officially "breaks".
Stick with high quality jacks and plugs for the durability. I like switchcraft & neutrik, in that order for quarter inch stuff. For XLRs, it's neutrik and switchcraft, in that order.
