Well, if you use the PD hardware in core audio mode, you can still use Logic like anyone would, and I think you'll fine that Logic has better plug-in efficiency that RTAS, and that Logic will allow you allot more AU instruments than PT will, and by quite a margin.
I use both, Logic for creation and tracking, PT for mixing (if I don't just use Logic, or need more power than I have, but with a few UAD-1 cards,and a UAD Duo, I have plenty)
Protools is awesome for allot though, editing, and some things.
Either way, welcome to the wonderful world of (il)Logic Pro, our favorite app to both love and hate. And of course, the LUG, which is the BEST place to get answers. There and a number of long timers here (and even a few since the Atari days of Notator).
Digidesign control surfaces only work with ProTools software. Digidesign won't allow 3rd parties to support them.
And as of ProTools 8.03 , Digidesign no longer allows 3rd party support for their TDM hardware via DAE (but you could still use it as the world's most expensive CoreAudio interface). This has actually made a bunch of people realize how awful DAE was with Logic, and how excellent CoreAudio is, in spite of losing the DSP horsepower of the TDM cards.