I purchased 8 of these combo packs for a small apartment building because I wanted the SmartKey feature and the price was right. Installation is fairly straightforward, except that the knobs have two, small nipples on the backside which I assume are designed to dig into the door as you tighten them down. The steel doors I was using were not soft enough to be punctured by the nipples so I had to file them off so the knob trim would fit flush against the surface of the door. Also the decorative trim is loose and doesn't stay in place around the knob without tapping the metal using a nail punch. The SmartKey feature is very convenient and extremely easy to use, but the locks don't feel as sturdy or well-built as other, higher priced products I have used in the past. Overall, the SmartKey feature is the real selling point here, whether or not they last remains to be seen.