I am not a locksmith, just a home owner with locks. I have about 16 Kwikset Smartkey locksets or deadbolts installed in two houses, and have had no problems with them. It was easy to key them alike, and would be easy to re-key them if a key were lost. (I ended up with lots of extra keys to choose from!)
I have done searches on Smartkey and found a few critics of the system, but also reports that they were secure. One critic suggested they were bad because a locksmith could not use conventional methods to open them without a key.
Besides Smartkey being "unproven technology", what other drawbacks are there?