No, it depends on the workflow

In the future, enterprises will be busy creating "custom" coding agents instead of using the standard off-the-shelf products. OpenCode fork + custom code instead of Claude code or GPT Sol.

I suppose that depends on what you mean by 'better'. If cost is your #1 consideration then, yes, definitely.

Didn't get a chance to use OpenCode or Kimi K3, however, i can safely say that (based on my use-case mostly cross repository task and somehow extensive) Fable 5 is much better than GPT 5.6 Sol.