Like clavguy said, extra plug-ins, for example, Isotope Mastering Essentials, and Acoustica 31 band eq. I wanted all the toys and have not been disappointed. Then again, I was starting from scratch - I didn't have a library of existing plug-ins that I had used in other daws.
Also, earlier in this thread, Acoustica Greg posted a link to the comparison chart you might want to look at.
I might also add that this forum is the BEST. The guys at Acoustica, as well as the regulars in here are always ready to answer questions and offer tips and information.

Again, welcome aboard.
Barry