What is the best DeFi aggregator?

Can you explain what exactly a DeFi aggregator is and what are the criteria that should be considered when choosing the best one? With the abundance of DeFi aggregators available in the market, it can be overwhelming to select the most suitable one for one's needs. Additionally, how do DeFi aggregators benefit users and what features should be prioritized in a good aggregator? It would be helpful to get an insight into the factors that set apart the best DeFi aggregator from the rest.