Polypropylene vs Brass

[dxiw]

besides looks what the difference?

[The Spyder]

I would use brass, reusable, it wont crack (polypropylene can) and it looks kewl!
Spyder

[Colin]

No real difference although polypropblene usually needs to be drilled out more than brass for optimum flow.

[Warlord2]

hmmm

polypropblene fittings are cheaper thin brass fittings:D