APO Product Options, Variants

This app has helped me to provide a greater amount of personalisation for my products than I thought was possible. I requested them to change the charge per character to ignore the spaces, and they changed the app within a few days, which I thought was excellent service.
They are very responsive to requests of support / additional information, and would not hesitate to recommend.
If I were to be picky, there are some limitations which I have found, which they have said will be improved in the next few months.