I mostly agree.. A it's easier to do complicated parts by brush, you just have a paper towel or cotton swab and mineral spirits to clean off any paint that gets on a machined surface like a way .
I do brush a lot of machinery, and like
@Ultradog MN says, a GOOD QUALITY china bristle brush, don't use a chip brush. I use quality Purdy brushes. They just hold and lay the paint better than a cheap brush.. just clean it good when you are done and you have a brush ready for the next time.
For best results use a primer.. I have short cutted that on occasion, and it shows. Do yourself a favor use a primer, and wait for it to be completely dry and then sand it lightly, or for a concours finish, sand it, and rinse and repeat until you can run your hand across and feel the beauty.