I am trying to find something or somehow to A/B.  I 'could' load each of the mixes into 2 tracks and then Solo and Un-solo them, but then there is that disturbing moment when both mixes are running, or simply silence when you've lost "the flow".  I've searched this forum for "compare" but found nothing.
 
Does anyone know how to A/B simply by pressing a button, you could flip back and forth between versions AT THE SAME LOCATION in playback?  Or software that allows this?

Create a Control group using the mute or solo buttons.
https://www.cakewalk.com/Documentation?product=SONAR%20X3&language=3&help=Mixing.41.html
 
You can also create a quick group toggle. 
 
- Select both tracks
- Press one mute button on one of the selected tracks
- Hold CNTRL and select the other mute button.
 
This in effect toggles the mute button on/off on selected track 1 +2.

chuckebaby
Create a Control group using the mute or solo buttons.
https://www.cakewalk.com/Documentation?product=SONAR%20X3&language=3&help=Mixing.41.html
 
You can also create a quick group toggle. 
 
- Select both tracks
- Press one mute button on one of the selected tracks
- Hold CNTRL and select the other mute button.
 
This in effect toggles the mute button on/off on selected track 1 +2.

Yeah, this is how I use to do it before I had the Magic A/B Plugin.
Would have probably still be doing it that way if the Magic A/B plugin didn't go on sell, which is how and when I copped it. Now that I have it and use it constantly, I can see the justification of the regular price point @ around 60.

How about using the "exclusive solo" button on the control bar...?

Use a DJ playback program... Can't remember the name of the one I used it was free ? But it had two cue lists that you could toggle or use a crossfadder. 
 
http://www.musicradar.com/news/tech/the-10-best-dj-software-applications-in-the-world-today-589833
 
Edit
Here, found it
 
https://www.virtualdj.com/
 
The other thing it does is will do tempo matching and vari speed.. lots of fun 
 

If I have two mixes and that I think are close, I export and load both into Audacity. I hit play and "solo" on each track back-and-forth to hear the difference.
 
Generally, I only have one mix and the "two mixes" tend to be mastering adjustments scenarios.

slyman
How about using the "exclusive solo" button on the control bar...?

If single tracks, this is the fastest. You will only hear the last track solo'd, all others get muted, so A/B your heart out.

mettelus

slyman
How about using the "exclusive solo" button on the control bar...?

If single tracks, this is the fastest. You will only hear the last track solo'd, all others get muted, so A/B your heart out.

+1. This is what I do.

slyman
How about using the "exclusive solo" button on the control bar...?

Ditto! I use this to easily A/B mixes and also load all the stereo tracks of an album I working on to quickly compare each song for volume, eq, etc. as a last check. (and it's free)
 
Walt