Depends on what you want out of it,as in are you using in in open areas and want good long distance or are you more in hilly built up areas?
I don't believe that it matters if its a stainless or fiberglass one, what you need to look for is the db rating.
3-4db (generally shorter) good for hilly built up areas
6-9db (generally quite long) better for open flat areas like touring around Aus.