I agree that the interface makes a big difference. Doing any mirror EQ work is significantly quicker when sources can be called up and isolated easily on one display.

Pro-Q2 is just fabulous...
Sonar's quadcurve
 

Thanks for the discussion.
 
Lately I am working at gaining a better understanding of EQ.  I like the visual representation of the QuadCurve and its Spectrum Analyzer, but there are many EQ's, like those in the BlueTubes bundle, that don't have either.  I'm forcing myself to use them and 'listen' to what they do.
 
 

The best para EQ is the one that YOU think is the best. Some like chocolate ice-cream and some like vanilla ice-cream. The same goes for all audio effects, including para EQ's.
 
What may be best for me can be worst for you. There are too many variables to consider.
 
There is no best or worst as it all has to do with personnel preference
 
CJ

One interesting EQ that I'll use is DMG Audio's EQuillibrium. The way it's designed from the ground up is revolutionary. It takes a bit of using to get the hang of it, but once you do, it's quite useful in all it's curves and options. Otherwise, I'll use the QuadCurve EQ (although I wish it were available in the standard FX bin), or DMG's EQuality, which is also quite flexible and useful. Flux Epure EQ is supposedly one of the best EQ's to surgically cut with. 

I've used Algorithmix Red/Orange/Blue in the past, but Algo all but abandoned (although they deny this) this REALLY EXPENSIVE, REALLY UGLY, but REALLY good set of EQs. 

If you enjoy the graphic EQ approach, I too am on the Pro-Q 2 bandwagon.  I really like Sonar's QuadCurve, but I just can't get into the ProChannel workflow and not having a VST version to allow for multiple instances in the FX bin pushed me to look at other EQs.
 
The Sonitus EQ is really nice, but the display is so small. :)  The full-screen display and tons of options with Pro-Q 2 is pretty sweet.
 
But I also tend to rely a bit much on graphic displays, so having the Blue Tubes emulations are nice as well.  I typically use the graphic EQ to search/destroy problematic frequencies or aid some air, but if I want some color/character I'll reach for the Blue Tubes.  Aside from the FabFilter stuff, I don't have a ton of third-party plugins.  Lots of cash and Sonar comes with plenty of tools to get the job done, especially if you dig the ProChannel workflow which many people do.

I used Sonar's QuadCurve for a few projects, but after trying a demo of FabFilter Pro-Q2, I haven't looked back. I love the interface and many features not found on QuadCurve. Try the demo for yourself...