Simply put, is not fit for purpose.

So, as a developer, I’m going to be a bit more “harsh” with this review.

So, installing is pretty straight forward, no real issues, and you can add fields to products just fine.

However, a few caveats.
It does not work for grouped products, only simple ones.
When viewing the grouped product, you can see the simple products “underneath”. There isn’t a way to add the input fields here without extensive re-templating (and I wasn’t paid for that, so I never tried).

Front-end work aside, the customer input does not show on the orders. Which is kinda the whole point of the plugin.

On another note, this does not work with WooCommerce product import.
Exporting seems fine, but importing does nothing, and I had to write up SQL just to sort that out. However, I am not sure if this is a WooCommerce thing.