What is the ERC (European Research Council)? Find more information here:

-ERC website
-Euresearch: the Swiss guide to European research & innovation

Q: Is it better to have a low or a high budget?

You have to budget what you need for your project. The budget needs to be realistic and well justified in this sense. The peer reviewers select the projects on the basis of scientific excellence, and not related to the budget. They don’t know how much money is left when evaluating the proposals. Possible budgetary cuts by the panels must be based on scientific evidence.