I have had three Chronys over the years, two expired from "lead poisoning". I still have the third but do not use it much any more as I prefer my CED M2's features better.
The Chronys always worked fine for me.
Like any chronograph, Chronys can be finicky when it comes to sensing the bullet, but the Chrony manual has some good trouble shooting aids. Things like sun position, sky condition, ground reflectivity, bullet size, muzzle blast, and more all can effect the reliability of the unit seeing the bullet.
Also, I would disconnect the battery when not in use and would keep a fresh battery on hand.
Wood dowels make suitable replacements for the metal rods that support the screen diffusers.
Take your time when shooting over the Chrony and remember the barrel/sight offset particularly with rifles. If you rush, you will shoot out your Chrony.
Enjoy your new toy.