Ranked in these QuestionsQuestion Ranking
Pro Compatible with a wide variety of devices
Pro Includes a backup battery in case power fails
If for whatever reason SmartThings loses access to tethered power it can still function for 10 hours on a battery.
Pro Has a Marketplace for user-submitted custom code
Adding extra code is as simple as copying and pasting the user submitted code. This allows for much added functionality and customization options.
Pro Automatic home/away mode
When all connected devices leave the house, SmartThings automatically goes into 'away mode'. Once a device comes back in range, it will toggle to 'home mode'. You will need to configure what these modes do (whether it be locking the doors, turning the lights on/off, changing the thermostat's temperature...), but it's great that this is done automatically when you arrive home or leave.
Pro Offers a detailed way of setting up scenes
Con Companion app can take a while to get used to
Con Pairing a device is more involved than it needs to be
Con Custom access isn't currently supported
Custom access is supported by other smart home ecosystems, but not with SmartThings. Custom access allows for things like configurable unlock codes for smart door locks, or allow access to certain SmartHomes products to certain users.