I'm cheap, so I've painted a couple of my machines lockdown bars and side rails.
I use Rustoleum "Hammered Paint"; it's getting difficult to get some colors now though.
There is also Masterchem Hammered Aerosol Spray Paint, which I haven't used...but will probably try next time as it looks like more colors are readily available.
I clean the areas that need it, and paint. The hammered texture covers a magnitude of sins, and is easily touched up as need be.
I repaint dented side rails right on the machine...just bondo the dents, and paint.
The powder coating looks great, but too expensive for me.