I have been an user of Cakewalk for over 10 years and I must admit, I have never experimented with the bounce options. I usually just use the Fast Bounce option for everything. However, I recently mixed a song down with the Fast bounce option unchecked and, I may be mistaken but, there was an audible difference in sound quality. The mix sounded more open and lively. 
 
Please let me know if my ears were deceiving me.
 
How do you mix down your projects?
 
Thanks, 

Hi. If I do not use external inserts, I use fast bounce as standard.
Must say that I cannot hear any difference.
All the best.

tried some times to see if there's a difference, but fast/nonfast were really the same (nulled).
iic checking '64 double precision' doubles the size of the files, so I have that unchecked always, and I never dither...but all these things don't make or brake things imo.
 

I have never detected a difference between fast bounce & real time bounce

Thanks for the feedback folks. I'll continue to play around with it.

According to Noel there is no difference in the quality of the resulting wave file. However, if I recall correctly there may be an impact on some few plugins. Not all plugins can handle a fast bounce. That may be a historical issue in that most new plugins are just fine with it. One symptom is a crash where a plugin can't handle it or a loss of sound quality. The is a simple way to check though using the null test.  
 
I prefer fast bounce for the time is saves. 

Within SONAR, there is no difference. Think of a slow bounce as a slowed-down fast bounce. Slowed so you can listen to it if you wish. Other than that, the math being performed under the hood is the same.
 
Of course, there are rare exceptions. For example, if you are low on RAM and have a slow disk drive that cannot keep up with streaming samples, you could end up with crackles or dropouts in the bounced audio that can be fixed with a slow bounce. But if you bounce a project and hear no artifacts, you can rest assured that you haven't sacrificed any quality by performing a fast bounce.
 

I've done both and haven't really heard an audible difference.
I currently use the "real time" bounce but that's more because it's usually not a time issue for me.
 
As John said, if your plugins aren't having an issue with fast bounce, there's nothing wrong with that.
Should (all things being equal) sound the same.

the brain has its ways of playing games with us.
this is one of them.

There's a whole cottage industry built around the fact that we never hear anything the same way twice, and how we can fool ourselves into hearing differences that don't exist. That's why there's a market for $1800 LP/CD/cable demagnetizers.