More rugged construction. Many aren't actually IP rated (cost money, Axxess is a small company) but I've had a motion outside under soffit for over a decade (somewhat covered, still exposed to weather, and it can reach -40 here in extremes....and no it doesn't matter what scale you use).
As an example that motion reads...well motion obviously, as well as temperature and humidity (though to be fair, so does the Nyce ceiling motion.
Overall Axxess items are just a bit more, dunno, durable feeling? Both companies have their own unique offerings as well (Nyce had a door hinge sensor, Axxess a simple doorbell to integrate, touch keypads and lamp adapters).
Note the garage tilt for nyce is discontinued - as is their mini keyfob control.