(almost) All L2s are essentially the same - so what matters is "CC" - Community and Connections (i.e. integrations you offer to builders and users alike).

Who has them ... here's your answer from Token Terminal 🤓

Base makes it easier for developers to build apps by offering seamless integration with Coinbase’s products, users, and tools. Access to 110 million verified users and over $100 billion in assets is kinda hard to beat advantage over building on other Layer-2s 😉
(apart from getting their airdrop money, ofc)

Base's advantage lies in its seamless integration with Coinbase's products and 110 million verified users, making it an attractive choice for developers and users alike.