I use cursor on auto mode almost all the time. I switch to Opus 4.7 when I need I know it will go off the rails. But generally Auto mode "just works".
For my personal work on my own projects, Codex 5.5 because it's cheap at $20 / month and I get in about 10 prompts during my work day (would be more like 40 if I was not focused on work though)
there is a significant learning curve to using AI well. learning to stay skeptical and keep your brain on, developing an intuition of how much free reign to give it, writing ironclad specs and design docs and keeping them updated, making work easy to inspect, the tone you use talking to it, using one agent to critique another's work, etc.
basically, AI will produce slop if left unattended. but it's not really its fault.. it's a process failing, like not supervising the interns. using AI the Right Way(tm) is a mental workout, quite a bit slower, but extremely rewarding (ime.)
For my personal work on my own projects, Codex 5.5 because it's cheap at $20 / month and I get in about 10 prompts during my work day (would be more like 40 if I was not focused on work though)