Bought three of these primarily for integration with Amazon Echo devices and based on the strength of the IPVM test. The Smartlock Pro is incredibly easy to retrofit in place. The first one took me a 30 minutes or so, but I had the others in place within 10-15 minutes each. The Smartlock Pro works really well. There are some minor gripes:
1. The coverplate over the battery is magnetic. No matter where I position it there is a grinding noise as the smartlock action seems to interfere.
2. Auto-unlock only works for one door per household. Auto-lock works on all doors.
3. It is a fairly large unit. Not entirely unsightly and the greater OD size makes it so that my preschooler can actually unlock doors to let our dogs out.
Despite the "Pro" moniker this is definitely no replacement for true access control. For home use it fits the budget.