Anecdotal, but after playing with the API this week (building a minimal harness for an OS where Claude Code isn't supported), the API felt faster to respond. It did seem like maybe the Max subscriptions are lower priority than API requests. (I hadn't enabled priority service on the API either.)

I don't have metrics, so I could be imagining this, or finally noticing extra lag of the Claude Code client. On the other hand, the API was giving me range anxiety, I won't be pushing a 300k context window into that anytime soon, like I occasionally need to do in Claude Code.