Which X3 features do you use the most, and which have you not explored yet?

So much new stuff made it to my PC since the X3 release, the biggest feature of X3 which I appreciate is stability with Melodyne a distant second. I have used comping a bit and the QuadCurve a little more because it is handy but all the other stuff; AAS, Blue Tube, XLN plug-ins, Gobbler, audio snap improvements... get no play. I really would like the QuadCurve HP/LP filter in a separate PC plug-in. This would get a lot more use than all the 3rd party plug-ins bundled in X3.

I am looking forward to using drum maps one day.

Yes, that is the idea. Multiple QuadCurve EQs would also be nice but a simple HP/LP filter does not need much screen real estate.

The ARA implementation of Melodyne was the highlight of X3 features for me.

If the Loop Constuctor does not qualify for this thread, then you seem to have named what I replace it with. I only looked into Gobbler to figure out if I had any actions to take to shut it off. It's harming me in no way though.

I think my favorite X3 feature is the stability I experience. I sometimes have 100 tracks or so going on and have yet to see any of the problems I see posted here almost on a daily basis. The Waves plugins GUI doesn't and never has disappeared, audio tracks don't mysteriously remove themselves, the program doesn't crash...folks it's not Sonar, it's your system ;)
 
Things I have no use for- Matrix, anything loop related(as a musician I play my own music but thanks anyways ;)),browser and multidock(what a waste of real estate!), Soundcloud.
 
Overall I'm very happy with X3, I just wish I could get rid of some of the clutter.
 
Bill

So which X3 features have you not explored yet? Or have you checked out most of them?

Which have I not used?  Probably 99%.   I already had Melodyne so that wasn't an issue for me.
For what I do, I could probably get by with Sonar 7.

I have found the colour coding of tracks associated with a bus a great but simple addition to X3. Auto track zoom was the feature that broke my resistance to the x series interface.

Pro channel is great.

The Matrix view is something I never use.

I love:
The comping feature.
Track follow buss color
Melodyne (all of it)
Console emulation

Haven't even touched:
Strum
Gobbler
Matrix
Loop construction
Audio Snap
AD

Good Points, Craig.  For me, I'm only recording Traditional Country (e.g. I'm currently recording a "retired" Nashville songwriter).  I use an Alesis SR-16 drum machine for the majority of recordings (I did a vocal project for the drummer in our band and even used the Alesis SR-16 for his project).  Vocals, add pedal steel guitar, lead guitar (clean, no distortion), bass and rhythm guitar and that's about it.  I've got repeat customers coming back for more projects so for my clients my formula works.

This should be a useful thread. As an exclusive Producer user my everyday activity makes good use of;
 
1. QuadCurve EQ (tremendous improvement and highly useful, especially in conjunction with Melda MultiAnalyzer (thx BitFlipper)
2. New comping implementation (only looping I ever do is multiple takes ...)
3. Melodyne ARA integration (great example of efficient functional integration, hope to see more examples of this approach)
+ 
Tone2 Bifilter2 (intriguing, one extra I need more time to play with it )
 
Not so useful
1. AD (longtime BFD user and not likely to change especially since BFD3. I did try AD, seems OK if not as deep as BFD)
2. Strum Acoustic Session (prefer real guitars)
3. Lounge Lizard (just not relevant, but I'm sure someone appreciates it.)
 
There are many extras and long time users have complained about yet another amp sim, but for a new user, the overall package is quite comprehensive and a tremendous value.
 
I think it's worthwhile to reinforce a couple of key points for the X series in general. 
1. UI
- Skylight may not be the best name, but given my background in the -science- of visualization, human interaction and  software design, I greatly appreciate the commitment to a major overhaul. Took some guts on the part of CW product mgrs, but absolutely worth the risk. Regarding the many complaints from some long time users, the insight is there are more than one type of users and the more "technical/engineering" types (my apologies in advance for general stereotyping) might have a preferences for the more "detailed" look & feel of say... 8.5. However, I generally see Sonar as a promising tool for the "creative" types (not that engineers are NOT creative, because they are) and the improved workflow and interactivity are greatly enhanced with the new approach. I find it to be a standout compared to the alternatives in my musical community.
2. Multidock/screensets 
- A subset of the UI improvements. Could there be improvements? Maybe, but quite useful as is. 
3. Stability
- This should be first actually. Cannot say enough about the accumulated confidence of daily use on several instances running Win 8.1 64x. But arent they all supposed to be rock solid? I marvel at the fact that it runs on a PC platform which is an infinite mess of variable conditions. Worst case scenario and yet we find utility undreamed at a mere decade or so ago ....
 

My favorite X3 feature.

Using:

• Comping (because I don't get a choice)
• Automation Lanes! (Yes yes a thousand times yes but please fix the paste bugs)
• Color customization (not ideal in my opinion but pretty good once I get used to bright wave/dark clip)
• FX Region with V-Vocal (it's new in X3 and works better than X2 so I'm counting it)
• XLN Addictive Drums (but you can't count this because I was already a full license paid-up user)

Not using:

• Melodyne (because V-Vocal FOR EVER!!!)
• Blue Tube (seriously... will they even be included in X4?)
• Anything new related to ProChannel (because I don't use it)

...I'm probably forgetting something.

I mentioned Pro Channel earlier, but I should specifically mention the Quadcurve EQ,I had plenty of EQ VSTs but this has made them redundant. Likewise the compressors and concrete limiter have marginalised many of my T-Racks plug-ins.
 
I have not dived too deep into Melodyne yet, even though I have upgraded to editor. I want to do more with it, extracting MIDI from Audio. I see potential for using my Mountain Dulcimer as a midi controller, albeit not in real time and using scat vocals as a way of getting melodies down.