Perhaps the way to look at it is ‘Which isn’t the worst bank in Spain?’ ‘Best’ and ‘banks’ don’t belong in the same sentence.
1. Santander, BBVA and La Caixa are probably the safest. I have a very low opinion of all banks in Spain, especially the cajas. They all over-charge. I don’t know that any have a good reputation.
2. In the Servired network (the biggest ATM network) withdrawls are free.
3. Probably Barclays. I’m going to do some research on this.
4. Can’t say. I’ve recently opened an online account with La Caixa called Cero (Zero) which is free so long as you keep to online banking and have a salary paid into it.
When it comes to banks in Spain, you have to be prepared to keep changing.
Sorry, can’t help you with a gestor in the Alpujarras.