My experience has been similar. I recently wanted it to write code to parse and process a rather strange data file into a list & dict. Here is what I found:

I went through a process of re-writing my prompt several times to get correct output. In fairness, I think getting the correct result meant being more precise with the prompting language.

Overall, it was a bit spooky seeing it respond to my varying prompts; then noticing it's errors; then re-prompting to fix its misconceptions. In the end, though I could have written it myself faster, so I am not sure it is saving me time.

I am surprised when I see people saying its saving them massive amounts of time. Are there any good examples out there of it producing copious amounts of code, correctly, from prompting such that I can easily believe using CoPilot is a time-saver?