Well I just use mild steel David – but some prefer stainless for obvious reasons.
However, I don't see why you shouldn't use brass – apart of course from the issue of it's colour (if unpainted) and/or (if painted) the fact that it doesn't take paint as well and if it does get 'chipped', then you get to see the brass showing through…
Mainly a matter of personal preference I suspect…
Regards,
IanT