Having used several diff brands, I can tell you, cheap & good do not come in the same sentence when it comes to chronographs. They all work about the same, the diff is the quality of the screens The screens are what give the measurements & the cheaper units, like Chrony, have the cheapest screens.
I have done back to back to back shooting sessions w/ an Oehler (best by far), Chrony & CED. Lining them up & shooting through all three. They all register within 8-10fps of each other. The big diff is how many shots get errors. The Oehler none, not one missed shot, even though it was the last to see the bullet. The CED missed less than 5%, the Chrony easily 45-50% misses shots, even though it was the first set of screens. Switchin it to the middle didn't help.
The problem is the Chrony screens are the smallest of the three & the most finicky about shot placement (why so many get shot). The shot MUST BE no more than 8" above the screens & pretty much dead center. ANy deviation, too high or as little as 1" wide, missed shot.
My recommendation, pony up & buy the CED. It's not an Oehler but pretty damn good. It's maybe $30 more than the most expensive Chrony, but the screens on all the Chrony models are the same, crap.