I've got mixed feelings on both. In my opinion por-15 is way more durable than powder coat but does not look as nice. I worked in my factories paint department for many years and we used a lot of powder. If its not applied right or at the right temp for the right time it flakes and leaves bare metal. On our system it went through a wash, then a light acid wash, then an electrostatic paint dip, pre heat oven, then powder coat followed by a 45 minute 475 degree oven cycle. I doubt many powder coaters are that meticulous. I'd like to see some pics of your por-15 on prepped metal. If you don't like it you can always top coat it with something else. That being said we are starting on my wife's 67 mustang coupe this winter and I'll be replacing some floor panels and doing a mini tub. It's going to be a pro touring/ restomod kinda thing and not a show car. She doesn't want a trailer Queen but a driver. We will be using por-15 on the whole underside of the car to stop rust.