Quality. Kwikset locks are among the lowest quality locks on the market today. However you will find them at every major Home Improvement store there is and the reason is because they are cheap and they do a good enough job. Schlage on the other hand produces their locks with more of an emphasis on quality and security. That being said both of the locks are mass produced for chain stores like "Home Depot", "Lowe's", and "Ace Hardware". As a security professional we sell both of the products but if our customers want real security we would recommend neither of them!
What is the difference between Kwikset & Schalge?
What is the difference between a Kwikset lock and a Schlage lock?