My priorities are miner decentralization (making it easier for small miners to predict the next block, and to propagate their blocks), and censorship-resistance, and keeping the UTXO set small, and helping Lightning-related fee-bumping.

A relaxed mempool policy ticks all my boxes.

Core30 is the only client that, by default, has the right mempool policy.

Many of the clients are quite configurable, which means you can choose your node software somewhat independently of your choice of mempool policy. For example, LibreRelay (and maybe even Knobs and Knots?) can be configured to be very relaxed.

I mention configurability because I would choose the Core client over the Knots client, even if I preferred the default policy in the Knots client. This is because Luke Dashjr, while definitely a genius who has helped Bitcoin a lot over many years, simply doesn't have the right software development processes. Each commit in the Core repository is signed, the builds are reproducible and the binaries are signed by many people. Knots is a joke by comparison. Bitcoin is too important to tolerate sloppy practices like that.