I bought one a couple months ago from a recommendation of one of my local track rat buddies.
It does work, but it's only as accurate as you are. If you're good you can get within plus or minus 0.1° . My buddy did 2 self alignments followed by double checking on a Hunter rack, and was within margin of error both times. It was really impressive to watch how much less annoying it was than setting up a string rig, which is why I bought it.
My biggest issue - you need to have the car on a near perfectly level surface for camber measurements, and my garage floor is fucked with cracks and angles. So I had quite a bit of work to do to get it to a workable space. I borrowed a surveying laser from work and had to shim up my ramps on 2 of the corners.
Also the 2023+ OEM wheels are a bit tricky to find a flat reference point to use.
Otherwise yes, it does work to the degree I need it to. Where I can go between my street alignment and track alignment with relative ease, just slide the camber plates the other direction and adjust the toe back to where I want after.