Sadly they won't implement thread anytime soon (I think @mike.maxwell said it would require a second zigbee radio so it wouldn't require time slicing) They are going to watch which way the wind blows first. I would love thread to be implemented in the next version just to open us up to some other products.
With Thread on board, this motion sensor should be significantly snappier than its Bluetooth-only predecessor. Thread is a mesh network that allows devices to communicate directly with each other rather than having to talk to a hub or bridge to receive commands. This translates to faster response time and lower latency. I’ve tested Eve’s Door & Window sensors in both Bluetooth and Thread versions, and the difference in response times was significant — going from 3 to 4 seconds to well under a second. It’s likely to be the same here, but we will be testing the sensor and will report back.
Wait. 3-4 seconds? Are there people who put up with that? 
I hope this one is well under a second, but the mere involvement of a hub is obviously not the reason anything should take that long (and to do anything complicated, I suspect you'll still need one; cf. Z-Wave Association vs. hub automations).
Yes, my mind kind of exploded when I read that. I would have time to walk into the room and do a short dance before motion would be sensed. Egads!
Everything is relative. If you were a Wink user, 3-4 seconds would be pretty snappy. Right now, they're waiting for lights to turn on from motion events that were triggered 22 days ago 
When I first started with HE, I went zwave. Someone here mentioned his wife doing the "zwave shuffle" waiting for the motion detector. Dead stop! Meanwhile, the zigbee camp was raving about the speed of the Iris v2 detectors. That was when I dumped zwave.
