Been awhile since I've been actively posting; just busy with stuff; thankfully we're getting through it and I can't complain.
I'll say this much: my good friend, who is retired, had one of these and he recently moved back to CO from here, so I don't get to hang with him as much; not only that, I miss his magneto!
I have a basic model 'shooting chrony', which uses the older, optical technology. It was a huge deal when they came down in price and I was able to get one; real game changer for my reloading and riflery. However, it truly is a PIA. lol
It is very finicky to ambient light messing with the sensors (the diffusers are great fun) and needs to be aligned 'just right' for bullet overflight, and leveled to get correct, consistent readings. You need to have it out in front enough of the rifle that the muzzle blast doesn't mess with it either.
At your own range, or a day that you are the only one at the public or club range, its not a huge deal, other than the OCD headache of futzing with it, but who wants to be that guy OCD'ing and tweaking the chrono on a tripod every time the range goes cold and hold the other folks up?
As stated in other posts, since these optical units are away and separate from the gun, you will not have a POI effect or other mechanical issue adding something unnatural to your shooting. That is the only plus.
But, if you are fine with working up loads by doing the velocity measurements separately from the seating depth tests or whatever else, the magneto is 100% the way to go, IMHO. Its so much easier and forgiving to setup. I will also add, that the measurements between the magneto and the shooting chrony nearly always agreed within a few fps, on days when we used both; that was kinda cool to see, with 2 completely, independent sensors.
I will do a plug for the shooting chrony folks for excellent tech support and customer service. They have been good to deal with. I just think that for the average guy, the magneto's newer technology is probably a better setup that gets you what need with less hassle. In fact, I hope one shows up for Father's Day or my birthday sometime in the future.