Payments
How you pay
One question only: if this deposit goes wrong, can you get the money back? That is about the payment method, not whether the book is honest. A good card can still sit on a bad site.
Easier to dispute
A card or a proper bank payment. If the book will not pay, you still have a bank or a card company to write to.
Mixed
Works on licensed sites. Getting the money back is slower, or there is no chargeback.
Hard to get back
Once it has gone, it has gone. That is not a judgement on the book. It is how the payment works.