I've had fantastic results with Magnetospeed Chronographs and I would highly recommend one. They're not an optical unit so they are not dependent on any kind of light source and are unaffected by any kind of changing weather conditions that may occur. They're extremely accurate and because they are so simple and easy to set up, they are nearly foolproof.
But, like ANY other chronograph, they aren't perfect. They'll only work on certain handguns and for obvious reasons they can't be used with arrows, so if you're a bow shooter a MS may not be the best unit for you. They tend to have some amount of POI shift when the bayo is attached to the barrel. All my rifles have at least a #5 contour with most being a little larger, my POI shift has always been very minimal but it has never affected my group size and that's typically the case for most but I have heard some claim it changed their group size. That's never been my experience but nonetheless it's a possibility so I'm mentioning it.
Since owning a MS chronograph, I use it A LOT more than when I had an optical type chronograph, simply because it is so very easy to setup and use. Someone mentioned they can have their MS setup and ready to use in less the two minutes, that is NOT an exaggeration at all and in all honesty, after you do it a few times, it's probably closer to one minute.
For most shooters the Magnetospeed Sporter model for $180 will do just about everything you'll ever need but if you have rifles with larger than 1 inch diameter barrels or you shoot suppressed then the MS V3 is what you'll want.