The only difference is that as customer, is that you purchased it with your Forum Coins. Donors get their status by donating money value to the website. They also have a monthly/yearly subscription, but must be monetary.
Customers are only elegible by purchasing the perk with the coins. You, for instance, bought it and will have it for a month.
What do you have? From now, a special forum which is only accesible by donors and customers: https://eprotv.org/forums/forum/13-donor-forum/
In the near future, there will be more benefits for both groups.