Over the last couple months I've gone from highly skeptical to a regular user (Copilot in my case). Two big things changed: First, I figured out that only some models are good enough to do the tasks I want (Claude Sonnet 3.7 and 4 out of everything I've tested). Second, it takes some infrastructure. I've added around 1000 words of additional instructions telling Copilot how to operate, and that's on top of tests (which you should have anyway) and 3rd party documentation. I haven't tried the fleet-of-agents thing, one VS Code instance is enough and I want to understand the changes in detail.

Edit: In concrete terms the workflow is to allow Copilot to make changes, see what's broken, fix those, review the diff against the goal, simplify the changes, etc, and repeat, until the overall task is done. All hands off.