Far too much is made of the supposed inaccuracy of optical chronographs. There are plenty of good ones out there, the competition electronics prochrono digital is one of them, that's what I use. I've got no experience with the F1 but have heard enough about them to avoid it. My prochrono digital is easy enough to check with my 6 BR. My 107 SMK load I use for 1000 yd shooting will be 2860 fps +/- 10 fps so long as it's between 50 and 75 degrees F. Until 10 minutes or so before sundown my prochrono will give me accurate numbers when I shoot that load across it.
I chronograph almost every shot when working up loads. I want to be able to chronograph while shooting for groups so the magnetospeed is out, I'm not going to shoot twice to get the data I need when I can do both in half the shots. It's just not necessary to do that to get accurate data. The Oehler 35P has long been the standard and the labradar looks nice, but if you're on a budget the prochrono will work fine. I don't get the fascination with a chronograph you have to hang off your barrel to get it to work, you just don't have to do that to get accurate number.