I've had one for about a year - I think it works great and believe it is worth the cost. Certainly there are much cheaper chronographs that give you the same information, but I like the quick set up especially on a public range. Mine has tracked .223 Remington with zero issues. Never tired .22 rimfire but did get it to read .17 HMR but only after figuring out placement of the unit so the lower muzzle blast activated the audible trigger.
Have had shooters on the adjacent bench and only twice that I remember did it react funny - and I think both times were near simultaneous shots from his bench and mine. Never an issue any other time even with some pretty busy ranges. Someone asked about cold - mine has worked normally at least down to the high single digits (above zero). Any colder than that, I would wait for a better day to shoot!!
Good product in my opinion and the ease of set-up has resulted in more use of the chrono during range outings compared to my old Shooting Chrony.
