The advantage of the SmartThing sensor is the added sensor suite. You have temp, vibrations, movement, and tilt. This makes it great for things like detecting is a washing machine has stopped running, or for use on a Garage Door opener, or for remote temp sensing, as well as the “default” option of open/close detection.
The advantage of the AEON sensor is that it’s Z-wave. (The SmartThings is Zigbee). This has two advantages: First better compatibility with systems other than SmartThings. If you decide to change systems later the AEON should work with ANY system that handles normal Z-wave products. There’s a far less likely chance that a system, even if it has a Zigbee radio, will be compatible with a proprietary sensor like the SmartThings multi-sensor. Second, many other common home automation plug in products (like light switches, outlets, Thermostats, plug in modules) act as Z-wave repeaters meaning you’ll have a better chance of getting a solid signal through to your hub if you’re a long ways away. Zigbee repeaters are a lot less common (The SmartSense motion sensor when plugged in does act as a Zigbee repeater).
So… in short: If you’re thinking that you may be changing systems in the next year or so, or if you are worried that your location of the sensor will be too far from the Hub for good communication, then I’d recommend getting a Z-wave open/close (like the Aeon item). Otherwise the added sensors and options for the SmartThings device make it more desirable in my opinion.