Personally I like the current Smartthings zigbee motion sensors. They have quick response, good battery life (easy to find battery model), good mounting options, and are easy to find if you are near a Best Buy.
There are lots of threads about motion sensors, including one linked to above, and I'm sure I've commented on them all. Not much has changed in the last couple years, except that the oft-recommended Iris v2 (model 3326-L) motion sensors are apparently really starting to disappear now, over a year after they were discontinued. The v3 sensors (IL_07) are almost as good and only a bit larger, but they do seem to respond a tad slower in my experience (still much better than Z-Wave). The Sylvania/Lightify motion sensor was made by the same OEM (Centralite) as the Iris v2, but Centralite had their own problems and I'm not sure if those are available anymore either. Centralite has their own "Miro" motion sensor (different design but still good reviews), which do seem to still be available, at least on Amazon (Centralite's own store has been down for some time).
For something that can be found easily and works well, I'd recommend the v5/2018 SmartThings motion sensors mentioned above. They're a bit larger than the others but have a nice adjustable mount, which you don't need to use if you don't want to. But regardless of which you use, my experience with pretty much any Zigbee motion sensor is that it responds faster and with less variation than any Z-Wave sensor I've tried (some of which have taken seconds to do so, some inconsistently so, but some are much faster than others though usually still not favorable to Zigbee). So no matter what you choose, you probably will be happier.
I have a bunch of zigbee motions as well. Don't forget to add some repeaters into your environment to help with this. I recently looked around and found that a lot of my zigbee devices are not powered. Added some zigbee plugs to help take care of that. Just thought I'd mention to keep that on the radar.