Ranking DeFi liquidation mechanisms: 1. Euler: dutch auctions are best at finding the correct spread to offer liquidators, but can be slow. 2. Fluid: gas-optimization definitely helps, but less of a factor when large loans are concentrated by user; offering liquidations as swaps may be powerful but there are issues in practice with integrating liquidations into aggregators, and in practice any market maker via RFQs can offer the same coincidence of wants execution for liquidations. 3. Aave: Chaos risk oracles help optimize the liquidation bonuses, but this is not as accurate as auctions. 4. Morpho: Pre-Liquidations help users control their own liquidation flow, although this modular construction is a worse UX for users, and less impactful for the protocol as a whole.