Hi Mick!
Good to see you around, been a while since we were struggling with getting X1 to work with our hardware ...
Just want to throw in that if you still want to have some sort of a control surface and not go all mouse, then hold on the to VS700C (ditch the vs700R, I reckon you will have a hard time selling that for real money) especially if check out all options and then decide to stick to Sonar.
Personally, I'm happy with what Sonar provides these days in terms of functionality and stability (later depends 99% on your audio interface, though, IMHO). I still run the vs700C but use several MOTU interfaces in a rather large setup. After such a long time mixing with faders and knobs under my fingers I would not want to got all mouse (and definitely not touch) but that's just me ...
Mixbus I got as well here. It's an interesting concept and currently much faster developing than Sonar (but it has also been lacking so much more), but overall it's not strong enough to convince me to use it more often.
I reckon if you come into recording from an old school tape machine / mixdesk mindset Sonar still provides everything and appears very usable. Plenty of music is created differently these days and so there are obviously better tools for other workflows.
My 50ct would be to think first which way you are going to work most with the software and check out which DAW suits you best. Of course, each one claims to provide everything these days. So it may be worthwhile to demo before you splash out. Not all that glitters is gold.