I was using 433mhz sensors with pilight. But now i have Xiaomi sensors. What i like about the motion sensor is that it is really small compared to the 433mhz ones. The price is not to bad either under € 10 for the motion sensor. And the motion sensor works with the Yeelight bulbs i have.
But you need the gateway which is used to control all Xiaomi devices it costs arround € 25.
Right now there is no official Home Assistant component. but there is a good working custom component.