I get very good results from Claude Code, something like a 3x. It's enough that my cofounders noticed and commented on it, and has had a lot of measurable results in terms of saving $ on infrastructure.
The first thing I'll note is that Claude Code with Claude 4 has been vastly better than everything else for me. Before that it was more like a 5-10% increase in productivity.
My workflow with Claude Code is very plain. I give it a relatively short prompt and ask it to create a plan. I iterate on the plan several times. I ask it to give me a more detailed plan. I iterate on that several times, then have Claude write it down and /clear to reset context.
Then, I'll usually do one or more "prototype" runs where I implement a solution with relatively little attention to code quality, to iron out any remaining uncertainties. Then I throw away that code, start a new branch, and implement it again while babysitting closely to make sure the code is good.
The major difference here is that I'm able to test out 5-10 designs in the time I would normally try 1 or 2. So I end up exploring a lot more, and committing better solutions.