EDIT: I've developed a problem.  Please look at the second post.  Thanks.
 
So far, I don't see any difference in function from SONAR X3. 
 
For those who may not know, V-Control Pro is an app for the iPad that controls SONAR.  I used to use a Frontier Design Tranzport, but I like this SO much better. The V-Control Pro app is expensive but it comes with emulations for all the major DAWs and a few other software programs like Adobe Audition.  The app works on early iPads, too, which is a great use for those.
 
If any of you are using V-Control Pro, you should consider getting active on the Neyrinck (the app maker) forum and request features.  Go to  https://forum.neyrinck.com/ and create an account.  They need to know SONAR users are using their app, and they should pay more attention to updating the SONAR skin.
 
 
 

[I reported this on the V-Control forum (Neyrinck) and await an answer there.]
 
In SONAR, Preferences, MIDI Devices, the checkbox for V-Control becomes unchecked, and checking it gives an error message: "Undefined external error".  Of course unless this checkmark 'sticks', V-Control Pro will not work.
 
V-Control Pro had been working fine on my system with SONAR Platinum.  Once before, I got this error and had to reinstall NeyFi to fix it.  Now the error is back.  I'm hoping someone here can assist.  It seems extreme to keep having to uninstall/reinstall NeyFi, which also requires a reboot.
 
Thanks.