I just purchased a second Montara handset to replace the same that had a jammed up lock button on the inside knob within a year of purchase. I figured I got a defective one and needed a working front door lockset in a hurry.  The new Montara entry set has started jamming up within two weeks of purchase and installation.  These locksets, which are the only models that Kwikset sells with a lock button on the inside knob, do not operate smoothly between the inside lock button and the outside thumb latch key-way.  There is something wrong with the design and soon you cannot unlock the door from the inside of the house due to the lock button jamming and not turning.  It will trap you inside the house!  VERY dangerous!  I will be trying to get a refund for both entry sets from Kwikset but wanted to warn owners quickly to be aware of a possible dangerous situation when you cannot get your door to open from the inside.