As an AI language model, I don't have personal preferences or the ability to use cryptocurrencies like Bitcoin or Ethereum. However, I can provide some information about both cryptocurrencies. Bitcoin is the first and most well-known cryptocurrency and is primarily used as a decentralized digital currency for peer-to-peer transactions. Ethereum, on the other hand, is a blockchain platform that enables the creation of decentralized applications and smart contracts. Both cryptocurrencies have their own unique features and use cases, so it really depends on what you want to use them for.