If you can delay the commitment for awhile I would wait for a demo version. Both Cubase and Sonar are incredibly powerful for the money spent. But bear in mind that you are going to be spending a great deal of time with your DAW...so if there is something in whichever DAW you chose that drives you bonkers you are going to get very tired of it over time.
 
Most DAWs seem to be in a process of leap-frogging each other. Cubase had VST3 first, Sonar was first with 64bit...Sonar now has ARA technology but Cubase has Note Expression.
 
I never thought I would have but it seems I have ended up a multi-DAW user and I can say that I can't really say I prefer one over the other. I prefer aspects of each one and I try to play to their relative strengths.
 
Between Cubase and Sonar my slant is this: Sonar for Workflow and logic that I understand. Cubase for look and feel. But they are both awesome.
 
Sonar can be run on a Mac using Boot Camp. I don't think you will ever see a native Mac version of Sonar because Cakewalk, particularly since X2a has really started to incorporate the 'Touch' feature set of Windows 8. That is an OS specific function call that could not be made in a Mac.
 
Good luck in your choice, regards,

I can delay absolutely. I have been working in Reason for years and will continue to do so. That little program is pretty darn amazing, basically I am just getting stuck on the orchestral stuff, there are just not any high quality libraries for Reason, at least not East West/Project Sam level. But Reason really works with my brain I have actually been thinking about setting up a host machine just for VST instruments since Reason 7 has midi out now. But once you go down that rabbit hole you want to start playing with VST effects and it just gets crazy at that point and it may make more sense to keep everything on one machine and do the orchestral scoring on Sonar, and the hip-hip/sampling/synth/mixing stuff in Reason. It am getting more and more calls for scoring to picture and while this can be done in Reason it is hardly elegant. So I am stuck and been evaluating my entire workflow. ugh. Anyway, keep the fantastic advice coming. I will get it figured out. Thanks!

If you're thinking about a host (slave) machine for your VST's, I highly recommend scrapping Reason and using Cubase or Sonar running VEPro 5. You simply connect up to four slaves via ethernet...works great! You can even run a free demo from http://www.viennaensemblepro.com/
 
The cool thing is, you can use a mix of PC and Mac. I have used it with both C7 and Sonar X2 and it is fantastic...especially for huge orchestral templates.

Sure, but the point is that I can still sequence in Reason because I love the workflow and sequencer. If I am scrapping Reason I would not need a another computer at all. But it sure looks interesting I will check it out!