It's a tough question. The big issue at the end of the day is the ability to make music, does the 700C impede this process?
Personally I find the surface under X1 does in fact impede the ability to create music without distraction. You just want gear that works as it should particularly when you have paying people around.
Right now the 700C does not function correctly and reliably outside of being fader and transport control. Realistically the Mackie unit would have done as good a job without losing so much time hunting for integration and the lack of it.
Make no mistake, right now, the only way to achieve tight integration with with the 700C and Sonar is under 8.5...crazy as it seems. If this is wrong then I would be thrilled to be proven wrong but we have all heard the deafening roar from our once supportive folk at Cake who I believe are really just being let down by their corporate masters at Roland. Welcome to the future folks.
Not sure which way to go with this.... the MCU is quite possibly again the surface of choice for Sonar? Or revert to 8.5?
Cheers.