Soundtrack Pro vs Pro Tools

Hi,

I have finished my edit in FCP and now will venture into sound work, cleaning up audio, mixing, etc...

I have never used either Soundtrack Pro or Pro Tools, I'm familiar with Audition. Anyhow this is an opportunity to learn one of these programs, any thoughts on either one for audio work for film?

Obviously, STP interacts directly with FCP so that would make things easier. Do I need anything special (hardware, plugins, ect...) for PT?\

Thanks