What do they do that SONAR just can't do?

OK, I'll start
 
Normalize using Average RMS

• (Sound Forge) "Noiseprint" noise reduction and the Wave Hammer multiband maximizer.
• (Wavelab) Level balancing when comparing processed and unprocessed versions of sounds.
• (Sound Forge, Wavelab) Create waveforms with sustain loops and do exports to samplers
• (Audition) Multiple clipboards
• (Most) Pencil tool for waveforms
• (Most) Pitch stretch/transposition with finer resolution than semitones

 
 

Just wanted to say thanks gents.
 
Dan - thank you for seeking ways to improve product from the community.
Scook - thank you for for being the most active to assist and typically right.
Anderton - thank you for your wisdom and forum presence. Your footer sums it up - still willing to provide an opinion (in this case fact) toward product improvement, seemingly independently of a company line/directive ... but as a result making the companies look better.
 

Sound Forge Pro - A stereo editor for waveforms, and what Craig stated.  Also to do Red Book prep for burning a CD with all the metadata.
Vegas Pro - A true video editor which is easy to sync the audio and burning DVD's with menu and metadata.
Finale - notation edition and printing sheet music.
 
And as ShellstaX stated, a thank you to Dan for thinking outside the box for Sonar.
 

Time stretch Render (I find Audio Snap mostly unusable)
 
Taming plosives and rogue peaks (faster than creating a bunch of tiny envelopes)

WaveLab - Phase scope
 
...prolly lotsa other stuff...but that's what came to mind that didn't get mentioned already.

I'm not near my DAW at the moment so off the top of my head , 
Samplitude , Spectral Editing , + The ability to edit the left or the right side of a Wave file independently while it is still a stereo file … 
 
Kenny

1. Per sample editing
2. Better waveform viewing
    I can view waveform in sonar, but it is pretty limited. Zooming options are insufficient for it. And I mean Track View. Now I've realized that I even can't zoom by wheel in Loop Construction view, and there is no cursor? I think that's one of the reasons I don't use Loop Construction view at all. And if I zoom in it too much it breaks.
   Representation of samples by bars may be useful, but sometimes I want to see interpolated waveform.
   Per sample representation in Track View is inaccurate. If I zoom in and set ruler in samples, ruler doesn't exactly match audio clip's samples, and sample number flowing label doesn't match them both. Also it doesn't show, and it is next item -
3. Sample Value
4. Spectral View
5. Playing very small selected part of wav file one time or in loop
6. Easy and clear wav conversions

I love Sonar and everything it does, but just at the end of the process I like to get out of Sonar (into Sound Forge) to top and tail, mp3 and get a slightly different perspective. No criticism just a habit! I was using Sound Forge a long way back and so am used to it.