Which eth network to use?

There are a few different networks that you could use for this purpose. However, the most popular option is Ethereum. This is because it offers a number of features that make it well-suited for use as a currency replacement. For example, it has an easily accessible smart contract platform, which allows users to create contracts and agreements that can be executed automatically. Additionally, Ethereum is backed by a powerful development community, which ensures that it will continue to be developed and improved over time.