They all work. Like autos, each has strengths and weaknesses with highly vocal supporters and detractors for reasons that seem good to them. Someone saying, "Mine works good for me" is useless for helping you make your decision. I always want to know why someone lauds or denegrates something and we rarely get much of that.
All of them are easy to set up. All give basic data such as average speed, standard deviation and extreme spread.
My chronograph is over ten years old now, it's no longer made, but has been updated and made better and less costly too. A good magazine writer did a review of several chronographs and I selected the PACT Pro largely from that. I made my choice after reading the list of features each model has, to the degree they actually give that info.
I wanted the guts and display unit on the bench, not in the line of fire and not all do that. I liked the idea of a built-in printer that would allow me to make a paper record of all I did at the range and only the PACT did that at the time (don't know about now). I wanted to be able to shoot multipule long or short strings and store the data for later review or printing. I liked the idea of a built-in program that would compute and print a ballistic table with programable variables like sight-in range, wind deflection, altitude, velocity, BC, recoil, impact energy, etc. So far as I know the PACT is still the only one that allows that versatility.
Others will have to tell you why they prefer their choice.
Any chronograph's screens must be set up correctly, at sufficent distance from the muzzle and shielded from direct sunlight getting in the photo cell slots.
