A bit of an oddball mouse, not many people ever had or used one. It really doesn't help that there wasn't much application support for them, or that they were fairly expensive. All in all it's a decent mouse for what it was intended for: 80s computers.
Well, how'd it come?
Not so great. Quite filthy, however it's also 20 something years old.

And all cleaned up. The blue wouldn't come off so I just left it.

How easy is it to setup?
Easy enough. It takes a hardware controller card which is the hardest part of the setup.
Step 1: Get a computer. My XT should work quite well.

Step 2: Install it (that's it under the AST cable)

Step 3: Success.

How comfortable is it?
It's not too bad. This here is a lot better than the blocks or soap bars that were ever so common in the 80s and 90s making it a nice choice for an old system. This particular one is a bit newer, although there were some older bricks.
If you're a lefty this mouse isn't a good choice for you. It's shaped for a right hand. While you can still use it with your left it's a bit odd unless you use your ring and middle finger for the left and right click buttons.

If you're a righty then this mouse works fine as it's designed for right hand use.

How's the performance?
It's not the best, but not the worst. It tracks somewhat slowly and it doesn't have the best accuracy, similar to a Trackball Explorer. Easiest way to show this is through a couple videos.
Tracking: Accuracy: In Conclusion
This mouse here is a fairly decent mouse if you need one in a quite old computer. It's far more comfortable than a brick or bar of soap while connecting through an 8-bit ISA slot so anything from a 5150 up can use it. I did confirm that it will work with Windows 2000, however I never tested anything newer as XP and up on a 200 MHz Pentium Pro sounds painful.
Out of 10 I give it a 7, simply for the fact that the accuracy isn't very great on Windows 2.03 or 2000 and the tracking is slow unless you adjust it, something you can't do in lots of old DOS and Windows programs.