I'm glad you brought up the power tool analogy - I've bought a $40 soldering iron once, which looked just like the Weller that cost like 5x as much. There was nothing wrong with it on the surface, it was well built and heated up just fine.

But every time i tried to solder with it, the results sucked. I couldn't articulate why, and assumed I was doing something wrong (I probably was).

Then at my friends house, I got to try the real thing, and it worked like a dream. Again I can't pin down why, but everything just worked.

This is how I felt with LLMs (and image generation) - sometimes it just doesn't feel right, and I can't put my finger on what should I fix, but I come away often with the feeling that I needed to do way more tweaking than necessary and the results were just still mediocre.