Agreed. I picked up a couple during Black Friday and just put one up at the front of the house this morning. I used a cheap arlo camera mount from ebay to attach it which allowed me to orient the sensor for the best coverage. The other one will go to the back. They really are excellent despite the high price.
I built this BLE beacon tracker, sort of (Raspberry Pi needed) and so far it's working perfectly.
I used these beacons NRF51822 2V 3.3V Bluetooth 4.0 Wireless Module For iBeacon Base Station Intelligent Control System Beacon BLE Module 4MA-in Integrated Circuits from Electronic Components & Supplies on AliExpress.
No idea about battery life at the moment though. Also there's the cost of the pi to factor in but mine's doing multiple duty including as a motioneye server and mqtt broker.