'lo all, I recently switched from using opcode studio vision pro (the red-headed step child of sequencing software,) to Digital performer 2.7. I would take a serious look at performer (http://www.motu.com.) It has a very nice interface, very advanced midi functionality, loads of plugins (plus plugins that allow vst compatability,) rewire support, and very advanced digital audio support. My fav feature so far (i've only had it for four days,) is the visual wave stretching feature. If you need to stretch out a wave, no more menus, just click & drag- very nice. FWIW, i spent about 4 or 5 months researching which one i was gonna buy.
just my 313 cents, out jim