I have quite a bit. I liked it.
In case you didn't already figure this out in research before buying....
If it's your first optical meter, don't waste materials in testing before you read directions and watch their videos on using the kit properly.

There are some very different considerations for the user in a kit like this (some even specific to this particular test) vs drip tests. Especially keeping the vials absolutely spotless and scratch-free. Unless you have something similar, buying one of their cleaning cloths isn't a bad idea if you want to favor the longevity of the glass.
Luckily, due to the liquid reagent, alkalinity may be the easiest of their kits to operate so it's a great one to start with IMO! (Out of the common ones, phosphate meters would be next hardest with calcium being the most difficult to operate correctly. With practice, I liked em all though.)
Hope this helps!
-Matt