AC Powered motion sensor - Need advice please

I only know of one zwave plug-in motion sensor that works well with SmartThings: the homeseer HSM 200.

http://www.smarthome.com/homeseer-hsm200-z-wave-multi-sensor.html

There are a couple of Wi-Fi motion sensors that have IFT TT channels, including one from WeMo and one from DLink, but you’ll get some additional lag with those.