There is no difference really. The ACCA only allow one Platinum provider and that is BPP. (The ACCA charge a lot more to be Platinum than to be Gold 🙂 )
All the materials are fine – you should choose whichever you find the easiest for you to work from.
(The reason we do not apply for our material to be Gold is because the cost is so high, but we are not charging people to use it.)