I hear a lot of people who have been trying out new DAWs and run across features SONAR has but the new DAW doesn't.  I'm sure there are a lot of cool things these other DAWs do that SONAR doesn't do or doesn't do so well.
 
One thing I have noticed is that in Bitwig and Mixcraft, it is a lot easier to layer instruments than in Cakewalk. I also like Bitwig's method of presets for FX better than Sonar's FX Chains.  What else?
 
EDIT - Add summary
 
Bitwig

• FX Presets
• Modulator System

Cubase

• Control Room
• MIDI - Note Expression, Chord Track, Chord Assistant, Chord Pad
• Score Editor

Reaper

• Extensions
• Routing
• Spectral Editing

 
Samplitude

• Controller editor
• Spectral Editing

Studio One

• Advanced Routing
• Scratchpad
• Studio One Remote

Bitwig' modulator system. Those are really awesome.

Reaper's tracks.

I like the midi editing in S1 using mouse wheel for almost everything, move, length, pitch, velocity..

The MixFX are pretty dang nifty in Studio One

Studio Ones Arranger Track and Scratch Pads, the Splitter, Extended FX Chains and Multi Instruments, as mentioned above the Mix Engine FX is pretty awesome, especially the CTC-1 Pro Console Shapper (very,very nice), the Project Page, the new Drop Out protection/ Low latency monitoring thinigy where you can have stuff, vsti's, for example, playing back at a high buffer setting while having your live input at low buffer/latency settings is pretty smick,  where to stop? and it'd not just a matter of 'what?' but also 'how?' it's the way Studio One does stuff, for example SONAR has ARA integration with Melodyne, as does Studio One, but Studio Ones is superior to SONARS, which is no surprise as PreSonus and Celemony developed ARA together.

Reaper:
* real-time waveform preview
* routing (especially in MIDI, including IN FX bin)
* speed
* extentions

Samplitude has Spectral Editing at the Track Level built in.  
That's something that no other DAW has.

cclarry
Samplitude has Spectral Editing at the Track Level built in.  
That's something that no other DAW has.

Reaper does.

https://youtu.be/vSBO_VC9q3E

Mixcraft has Melodyne, like Sonar AND cool stuff like changing a song's pitch, tempo, and time sig using markers... COLORED markers.
 
You can also set a marker at 0.00 and change these params for the whole song to see which settings sound best.
 
Each track has built in FORMANT so you can keep your voice/instrument sounding normal.
 
All this w/o time stretching, processing effect, or bouncing.
 
Each clip has it's own play, mute, & loop buttons. You can duplicate a clip as many times as you click the button creating a loop as long as you want. Loops are glued together. You can remove a looped section by highlighting & cutting it.

Samplitude has ARA integration, but my favorite features so far that Sonar doesn't have are 1) A full on controller editor that can edit all the button assignments on my ProjectMix (Mackie). 2) Revolver tracks. 3) Loads of metering and analyzers built into the GUI that are very easy on the eye. 4) The concept of virtual projects. 5) The hybrid audio engine.