Doors and Windows - Door Knobs

Hi. I am going to change the door knobs in my house and am wondering if there is really any difference in quality between brands?

The ones available here are mostly MasterLock, Weiser and Schlage, but there's also a few really cheap ones...

Aren't they all pretty similar when it comes to quality?

Not in my opinion. There are different grades within each brand, but the better ones start at a higher level. Don't buy the cheapy in any brand, for an outside lock. Interior passage locks/knobs don't usually require the better components. For good exterior locksets, I like Schlage or Qwikset. But for really good locks(and $$$$$$), look at Baldwin or similar.

Better locks usually have better engineering, heavier steel components and better finishes. The better ones offer lifetime(not sure whose) finishes that will take years of bad weather. Cheaper brands quickly tarnish or rust.