Works great

Perfect!..ok .

Perfect trackball. Not *quite* as big as trackballs in full arcade machines, but most DIY machines are looking to be all-in-one machines, so this is sized perfectly to work great and not take up too much space.
Note that this requires the 12-in-1 I/O board if you're going to use it with a PC, Raspberry Pi, or similar device, but as of January 2024 this is very clear in their documentation. It's very easy to add it to the 12-in-1 board, but just make sure you read the instructions and plug it into the correct port...it won't break anything, but it won't work correctly in the wrong port.
The documentation could have been a bit clearer about how to get to the jumper to remove it for increased sensitivity, but it's still easy to work out that you have to open it to get to it. The only ding I will give this is that it's a bit scary to have to open it to remove the jumper. Do-able, yes, but you have to be careful when unsnapping the top so as not to break it. Go slow, be careful, and it will come apart (I used a thin sturdy piece of metal to work under the tabs and carefully pry them to release the top). Making that easier to do would be the only change I would recommend (e.g. only snap on one side and the other side be a pivot would have made removal of the top way easier and less scary). You will also have to open it up every so often (like, every couple of years or so) to clean the rollers...so having this access be easier and less scary would be nice.
The RGB is not overwhelming at all and easy to adjust on the fly with the jumpers. It's obvious that the team at GRS knows their stuff and works to provide home arcade gaming fans excellent peripherals to make their projects work fantastic.

I must not have read the initial listing for the trackball properly, because I didn’t realize that the 12-1 encoder was required. So I ended up paying shipping for two tiny little things. I wish the wiring for the trackball was maybe another 6” longer, as I’m using it in an alternative manner. That said, it rolls smooth, accurate, cool LED lighting. Definitely recommend.

Easy install, works great!