I had fork legs powder coated in the past. It was much more expensive than painting them DIY. It was a nice hard, glossy finish but where you would put a light scratch on a painted fork the powder coat came away in chips leaving a much more damaged looking finish.
I’ve also had suspension components on a car powder coated and they got a gravel rash look almost immediately.
I’m sure it can be done well, i.e. the factory finish on some bike frames. But… I’ve never seen a really nice job from a local business.
I’ve stuck to rattle cans ever since. The halfords stuff for nice colours and Hammerite for anything black and out of sight. The quality of the end result is down to how anal you are with the preparation. I’m no pro but I’ve done loads of frames and forks in the garage that came out good enough for me.