I really doubt they'll swap in Grok. Grok seems pretty dead. Probably more likely they'll reuse the hardware for composer.
If value is a concern, Codex. It's pretty hard to beat those subsidies. If you really want model freedom, Copilot is surprisingly decent value and as of right now let's you use your sub in other harnesses like OpenCode.
Codex is not a replacement for an IDE. Yes I still need an IDE.
When coding agents work they're great. When they don't I still need the IDE. They usually don't work that great when I'm working on something novel or brownfield. Which happens quite regularly.
But I definitely still want ai autocomplete. I'm not a Vim user. Coding isn't about typing for me, it's about solving problems. So a tool that does lots of the typing for me is a godsend.
So do I go for VS Code + Copilot? Because it was bad when I tried it again for a few days in November. Slow to respond and gave poor results. Cursor is snappy and gives useful results most of the time.