For the money they are the top of the heap. 

40 Rod

I use the pro chrono also!

Terry

I like my chrony just fine, but a mate at our range that holds national F class records is using one of these.  Nice, but spendy
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The Chrony is so inexpensive that it is worth getting one even if you only occasionally check velocities of loads.  As far as I've been able to determine, it shows the same velocities as other chronographs for the same guns and loads.

The only troublesome aspect of the Chrony I've found is its sensitivity to light quality.  If the ambient light is too bright, or at too extreme an angle (mornings or evenings), the error readings start to show up.  This problem will generally go away if I tape a target or other piece of white paper over the diffusers.  Alternatively, I just wait for a nice overcast day, what I call "chronograph weather."