The best chrony is the one you don't shoot. (Don't hit it and break it. Seen that lots, even did it once).
Window type chrony are cheapest, easiest to get into, however on a gun range are annoying if it's a public range, as you have to walk forward of the shooting line to put it out.. often requires range closure, etc..
Magnetospeed are a different option which clamps to your barrel, unless you get another upgrade to get it to clamp to arca / pic rail, etc. Any sort of accuracy testing while clamped to the barrel can be hit or miss. Velo is great, accuracy will suffer as you have a weight on the barrel. Also basically not compatible with pistols, and some rimfires have issues from barrel size, so requires some... Creative ideas.
Labradar is a simple setup and usually work. Some people have issues with them triggering, but do work when setup. Batteries SUCK, so you need a USB brick to power it.
Multiple people at the range can give weird results sometimes when it triggers off their shot.. 10,000fps, etc...
There's others, however cheap entry, basically any "cheap" window chrony will do. You also get what you pay for.
Note: chrony's are accurate to THEMSELVES. If you do load dev for velo on chrony brand X, do all of it on that. Don't do some, then borrow a mates or the club/ ranges hire unit. They will read different.