Sounds like we have another very cool choice, as far as DAWs are concerned. Cross-Platform is a Big +.
I'm not sure, but will it run as full 64-bit DAW on Vista-64 ? Hopefully it does, and also run as a 64-bit DAW on the next Mac OSX Snow Leopard.
My experience with Presonus products has been wonderful. They make solid products.
I have their "Central Station", and "ADL-600" Tube Mic-Pre. Both have been great ! Hopefully their new DAW venture will be a class act as well.