Every one of the four powdercoat finished frames I have chemically stripped has shown hidden rust developing under the finish, even if it does not show from above.
These were all single stage coated frames.
The firms mentioned who do durable work all do multistage.
This of course drives up the cost.
For $80. I think you will get a single stage job.
I have only had one frame done where I selected the coater.
It appeared great for 18 months, then started to fail at braze ons and lug points.
Any powdercoater will advise that a "sharp" or 90° edge is a challenge. The physics of the material as it changes from solid to a liquid cannot be avoided. Multiple stages help mitigate this.

I would DIY if you cannot stomach the cost of a multistage job or traditional painter.