Profits generated are used to purchase more of the underlying asset of each vault (e.g., the ETH vault's profits are used to purchase additional ETH); therefore, the vaults represent a continuous buy-and-hold strategy. Withdrawals are allocated on a pro-rata basis determined by the share each depositor contributes to the vault.
Each chain can have multiple types of vaults. Check our App for a current list of all vaults and which vaults are currently available to participate in. Tokens are deposited into their respective vaults and are then reinvested based on the best current opportunities in the market.
For the end user the main difference is the chain of choice, i.e. Ethereum, asset utilized and vault strategy. The relevant section in the FAQ has more details. Once you understand it, pick the vault that matches your chain, tokens and the APY desired.