First I haven't RTFM.
 
I just started using. I'm guessing I'm not alone.
 
I used to make copies of projects as I went, but I've been working on a lot of mixes just using the scenes now.
 
Scenes are bit like code branches. It seems to save when you leave a scene for another regardless of whether you hit the save button.
 
Scenes do not get duplicated when you save your project under another name. Consequently, scenes can be corrupted if you open and close projects saved off under other names but in the same folder as your primary project name.
 
Making a TON of scenes works best. If you want to play with a scene (but maybe not keep changes) bring up the scene and immediately save as new scene (sandbox scene maybe).
 
These are my thoughts so far. Anyone else making similar discoveries?

Haven't used them yet... Too frightened.

I use them at decision making time. Create different mixes, make a decision, implement it and done. I haven't tried keeping a bunch of mixes in a project to use again after. That seems like the obvious next choice to explore however.

Good observations:

>>I used to make copies of projects as I went, but I've been working on a lot of mixes just using the scenes now.
 Yes this is a major benefit.
 
>>Scenes are bit like code branches. It seems to save when you leave a scene for another regardless of whether you hit the save button.
 
You can disable this behavior if you don't want it in the Mix recall preferences. Turn off the autosave when changing scenes flag. That can be useful but there are cases when you don't want it. 
 
>>Scenes do not get duplicated when you save your project under another name.
Correct, scenes are shared when you save a project under a new name but in the same folder. Its the same as the audio data. If you truly want a copy you should use per project audio and save to a new folder. Then the scenes will be copied to the new location and unshared.
 
 

Used scenes in one project so far.
 
Only one odd glitch (only happened once).
 
One VST (Slate's FG-X) reset to "zero" on one scene (of two) after 4 or 5 quick back and forths. Can't duplicate it yet.

For me Mix Recall is by far the best / most useful of all new features.
 
While I had some initial issues with it, I really appreciate that they have been quickly addressed in the past 2 updates.
 
Batch exporting of mix versions is a killer feature with plenty of applications and a true time saver.

It would be cool to have a fresh start button that created a new scene with no effects.

You can do that by resetting the mix with only the FX checked in the Mix recall settings, then saving it as a new scene.

So cool! Thanks FBB!