Jeff Evans
Gain knob is not required in Studio One.  What you can do in Studio One is simply edit the volume of any audio event on a track (individually which you cannot do with the gain knob effecting a whole track so its actually better) by simply grabbing the gain handle and raising or lowering.  Unlike Sonar you can see the changes in waveform height immediately.  After a while you can get pretty savvy at just looking at waveforms and getting all their rms levels very consistent.  Before you start a mix.
 
If you track properly as well using a VU meter you will also never need a gain knob either.  It is when you get material from someone else that has done the tracking that you are more likely to see inconsistent rms levels on tracks.  In that situation I tend to open them all up one by one in an editor and with a VU over the tracks make all the adjustments there.  It is far more accurate than fiddling a gain knob. 
 
As far as the mixer is concerned it depends on who you are talking to.  I don't like the Sonar mixer at all but love the Studio One mixer.  So sorry it is not the best mixer in the world!  Mixbus mixer is also pretty cool too. 

+1000.  Totally don't need a gain knob as Jeff pointed out.  Select all the audio and use the gain handle to adjust it all at once at once if you like, instead of one track at a time.  Also, its super fast in Studio One is to set up a macro to normalize all audio to whatever level you want to drive your plugins in your template at optimal levels and strip silence for all tracks.  Do all this in one step for all tracks as part of mix prep with the press of one key.  Again, no trim knob necessary.  It would actually slow you down alot.  And how about a console track list in Sonar?  Before I really switched to Studio One and MixBus, Sonar console navigation was really slow and frustrating on high track counts projects.  Also, from what I can tell, track folders don't appear on the Sonar console, and again, the faders are insanely short.

Plus the fact the Studio one faders can be set to any height as well.  Forgot to mention.  When the Studio One mixer is open on a second screen it can be fully vertically extended as well showing all inserts and sends at once.  Presonus plugins as well can be put into a little thumbnail mode right in the mixer.  Parameters can also be tweaked without opening the plugin.  The fader also has a little meter to the side showing gain reduction when compressors are inserted.  Mixer can be put into narrow or normal mode as well.  The Faderport 8/16 can bank mixer channels real easy making navigating a huge mix very easy and fast. 
 
The more you think about it the Sonar mixer seems less and less like the best mixer in the world.

Such a subjective question. There is no 'best mixer in the world'. All will have their fans and detractors, though some fans have certainly proved more evangelical than others:)

The best mixer (for you, not in the world) is the one you know.

It would be nice to have fader throw lengths in 2 or 3 different sizes, and t put the buses with with there assciated tracks, but other than that, I'm happy with console View styling.

It could be by some, but then some other people wouldn't agree.
 
HTH

I agree but I also will continue to call it Sonar's mixing console. When Bandlab "enhances" and "adds functionality" like some mentioned above, I will then refer to it by the other name.

Jeff Evans
Mixbus mixer is also pretty cool too. 

Or in my world the best mix console.
 
But I do miss this from my hardware days.

BenMMusTech
Sonar's (I refuse to call it CBB)

Why? That's what it's called now. Might as well refer to things by their actual name, yes? 

Jeff Evans
 
The more you think about it the Sonar mixer seems less and less like the best mixer in the world.

Even when I mix in SONAR/CbB I still only work in TV after all these years.